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1Presentation_ID © 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE
Introduction to IS-ISIntroduction to IS-IS
NANOG 20, Washington DC October 22-24
Abe Martey
amartey@cisco.com
2© 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE
TopicsTopics
1. IS-IS Overview
2. IS-IS Protocol Concepts
3. CLNP Addressing
4. IS-IS Database
5. MPLS TE Extensions for IS-IS
6. ISP Network Design Considerations
7. Configuration Examples
8. Basic Troubleshooting
9. Further Reading
1. IS-IS Overview
2. IS-IS Protocol Concepts
3. CLNP Addressing
4. IS-IS Database
5. MPLS TE Extensions for IS-IS
6. ISP Network Design Considerations
7. Configuration Examples
8. Basic Troubleshooting
9. Further Reading
3© 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE
1. IS-IS Overview1. IS-IS Overview
Terminology and Acronyms
Intermediate system (IS)- RouterDesignated Intermediate System (DIS) - Designated RouterPseudonode - Broadcast link emulated as virtual node by DISEnd System (ES) - Network Host or workstationNetwork Service Access Point (NSAP) - Network Layer AddressSubnetwork Point of attachment (SNPA) - Datalink interfacePacket data Unit (PDU) - Analogous to IP PacketLink State PDU (LSP) - Routing information packet
4© 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE
IS-IS OverviewIS-IS Overview
• The Intermediate Systems to Intermediate System Routing Protocol (IS-IS) was originally designed to route the ISO Connectionless Network Protocol (CLNP) . (ISO10589 or RFC 1142)
• Adapted for routing IP in addition to CLNP (RFC1195) as Integrated or Dual IS-IS
• IS-IS is a Link State Protocol similar to the Open Shortest Path First (OSPF). OSPF supports only IP
5© 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE
IS-IS OverviewIS-IS Overview
• IS-IS is an Interior Gateway Protocol (IGP) - for Intra-domain (AS) routing
• BGP provides inter-domain routing for IP networks
• ISO-IGRP is a Cisco proprietary routing protocol that can be used between CLNP domains
6© 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE
IS-IS OverviewIS-IS Overview
• 3 network layer protocols play together to deliver the ISO defined Connectionless Network Service
- CLNP
- IS-IS
- ES- IS - End System to Intermediate System Protocol
• All 3 protocols independently go over layer 2
7© 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE
IS-IS OverviewIS-IS Overview
• CLNP is the ISO equivalent of IP for datagram delivery services (ISO 8473, RFC 994)
• ES-IS is designed for routing between network hosts and routers (ISO9542, RFC 995).
• IS-IS for layer 3 routing between routers. (ISO 10589/RFC 1142). Integrated IS-IS (RFC 1195) works within the ISO CNLS framework even when used for routing only IP.
8© 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE
IS-IS OverviewIS-IS Overview
• End System Hellos (ESH) from Hosts and Intermediate System Hellos (ISH) from Routers used for ES-IS neighbor discovery
• Intermediate System to Intermediate Systems Hellos (IIH) are used for establishing IS-IS layer3 adjacencies
• ES-IS is somehow tied into IS-IS layer 3 adjacency discovery. ES-IS enabled automatically when IS-IS is configured on Ciscos
9© 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE
2. IS-IS Protocol Concepts2. IS-IS Protocol Concepts
• Nodes
• Links
• Areas and Adjacencies
• Level-1 and level-2 routing
10© 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE
IS-IS Protocol ConceptsIS-IS Protocol Concepts Network NodesNetwork Nodes
• Hosts
• Level-1 Routers
• Level-2 Routers
• Level-1 and Level-2 Pseudonodes on broadcast links only
11© 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE
IS-IS Protocol ConceptsIS-IS Protocol Concepts Network NodesNetwork Nodes
PSN
DIS DIS
• Broadcast link represented as virtual node, referred to as Pseudonode (PSN)
• PSN role played by the Designated Router (DIS)
• DIS election is preemptive, based on interface priority with highest MAC address being tie breaker
• IS-IS has only one DIS. DIS/PSN functionality supports database synchronization between routers on a broadcast type link
12© 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE
IS-IS Protocol ConceptsIS-IS Protocol Concepts Network/Link TypesNetwork/Link Types
• Point-to-Point Links (PoS, ptp FR, ptp ATM)
• Broadcast Links (Multi-point/multi-access, ie Ethernet, mpt FR, mpt ATM or Cisco DPT)
• Non-broadcast multi-access treated as broadcast or
point-to-point by configuration
13© 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE
IS-IS Protocol Concepts IS-IS Protocol Concepts AreasAreas
L1L2
L1L2
L1
L1
L1
Area 49.001
Area 49.003Area 49.0002
L1L2
Level-1Area
Level-1Area
Level-1Area
Level-2 Backbone
14© 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE
IS-IS Protocol ConceptsIS-IS Protocol Concepts IS-IS AdjacenciesIS-IS Adjacencies
• IIH advertised for detecting neighbor and forming network layer adjacencies
• 3 types of IIHs:
– Point-to-point
– LAN Level-1
– LAN Level-2
15© 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE
IS-IS Protocol ConceptsIS-IS Protocol Concepts Point-to AdjacenciesPoint-to Adjacencies
• Pt-to-pt IIH used to establish level-1 or Level-2 pt-to-point adjacency
• Only two way communication required on pt-to-pt links by ISO 10589
• 3-way reliable process recently proposed for standardization in the IETF. Introduces pt-to-pt adjacency state TLV (Type 240)
Intra-domain Routing Protocol Discriminator
Length Indicator
TLV Fields
Version/Protocol ID Extension
ID Length
R R R PDU Type
Version
Reserved
Maximum Area Addresses
Reserved (6 bits)
Source ID
Holding Time
PDU Length
Local Circuit ID
Circuit Type
Bytes
1
1
1
1
1
1
1
1
2
1
ID Length
2
1
Variable Length
16© 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE
IS-IS Protocol ConceptsIS-IS Protocol Concepts LAN LAN (Broadcast link) Adjacencies(Broadcast link) Adjacencies
• LAN Level-1 and LAN Level-2 IIH multicast independently to AllL1ISs (01-80-C2-00-00-14) and AllL2ISs (01-80-C2-00-00-14)
• 3-way reliable adjacency formation can be enforced due to IS neighbors TLV (Type 2) appended to LAN IIHs
Intradomain Routing Protocol Descr.
Lenth Indicator
Version/Protocol ID Extension
ID Length
PDU TypeR R R
Version
Reserved
Maximum Area Addresses
Reserved/Circuit type
Source ID
Holding Time
PDU Length
Priority
TYPE LENGTH FIELDS
bytes
1
1
1
1
111
1
1
ID Length
2
2
1
ID Length + 1
Variable
R
Lan ID
Holding Time = Hello Interval x Hello MultiplierPriority - Interface Priority for DIS arbitrationLAN ID - System ID of DIS + PSN number
17© 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE
IS-IS Protocol ConceptsIS-IS Protocol Concepts Hierarchical RoutingHierarchical Routing
Area 49.001 Area 49.0002
Level-1Routing Level-2
Routing
Level-1Routing
• IS-IS supports 2-level routing hierarchy
• Routing domain is carved into areas. Routing in an area is level-1. Routing between areas is level-2
• All ISO 10589/RFC1195 areas are stubs
Backbone
18© 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE
IS-IS Protocol ConceptsIS-IS Protocol Concepts IS-IS Packet TypesIS-IS Packet Types
• IS-IS Hello Packets (IIH) Level 1 LAN IS-IS Hello
Level 2 LAN IS-IS Hello
Point-to-point Hello
• Link State Packets (LSP) Level 1 and Level 2
• Complete Sequence Number packets (CSNP) Level 1 and Level 2
• Partial Sequence Number Packets (PSNP) Level 1 and Level 2
19© 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE
3. CLNS Addressing3. CLNS Addressing
• NSAP Format
• AFI Values
• Requirements and Caveats
• Examples
• Globally unique NSAPs
20© 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE
CLNS AddressingCLNS AddressingNSAP FormatNSAP Format
System ID NSELAFI Variable length Area address
6 bytes 1 byte1 byte 1 - 12 bytes
• NSAP format has 3 main components
– Area ID
– System ID
– N-Selector (NSEL) - value is 0x00 on a router
• NSAP of a router is also called a NET
Area ID Sys ID NSEL
21© 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE
CLNS AddressingCLNS AddressingAFI ValuesAFI Values
• X.121 - Int’l plan for public data networks
• ISO DCC - Data country code
• IS0 6523 ICD - Telex
• Local - For local use within network domain only
Address Domain AFI Value
X.121ISO DCCISO 6523Local
37394749
22© 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE
CLNS AddressingCLNS AddressingRequirements and CaveatsRequirements and Caveats
• At least one NSAP is required per node
• All routers in the same area must have a common Area ID
• Each node in an area must have a unique System ID
• All level 2 routers in a domain must have unique System IDs relative to each other
• All systems belonging to a given domain must have System IDs of the same length in their NSAP addresses
23© 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE
CLNS AddressingCLNS AddressingRequirements and Requirements and CaveatsCaveats
• Multiple NSAPs allowed on Cisco routers for merging, splitting or renumbering
• All NSAPs on the same router must have the same system ID.
• The maximum size of an NSAP is 20 bytes
• Minimum of 8 bytes allowed on Ciscos. 1 byte for area, 6 bytes for system ID and 1 byte for N-selector.
AFI prefix recommended to make minimum of 9 bytes
24© 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE
CLNS AddressingCLNS AddressingNSAP ExamplesNSAP Examples
Example 1
47.0001.aaaa.bbbb.cccc.00Area = 47.0001, SysID = aaaa.bbbb.cccc, NSel = 00
Example 2
39.0f01.0002.0000.0c00.1111.00Area = 39.0f01.0002, SysID = 0000.0c00.1111, NSel = 00
Example 3.
49.0002.0000.0000.0007.00Area = 49.0002, SysID = 0000.0000.0007, Nsel = 00
25© 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE
CLNS AddressingCLNS AddressingHow do most ISP define System IDs?How do most ISP define System IDs?
Router A#Interface Loopback 0IP address 192.168.3.25
Router isisNet 49.0001.1921.6800.3025.00
IP Address conversion process:
192.168.3.25 -> 192.168.003.025 | V
1921.6800.3025 | V
49.001.1921.6800.3025.00
26© 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE
CLNS AddressingCLNS AddressingGlobally Unique NSAPsGlobally Unique NSAPs
• AFI 47 (ISO 6523 ICD) is allocated via national sponsoring authority of the International Registration Authority (RA), usually a national standards body
NIST - allocated IDI 0005 and 0006
BSI subsidiary IOTA allocated 0124 for assignment of ATM End Systems Addresses
• AFI 39 also administered through national institutions
IDI 0840 allocated to ANSINIST - United States National Institute of StandardsBSI - British Standards InstituteIOTA -Identifiers for Organizations for Telecommunications Addressing
27© 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE
47 0124 XXXXX YYYYYYYYYYYYYY AABBCCDDEEFF 00
AFI IDI ORG ID ORG ASSIGNED SYS ID NSEL
CLNS AddressingCLNS AddressingGlobally Unique NSAPs Globally Unique NSAPs
Globally unique NSAPs make sense for interconnected telecommunications systems such as ATM switches, SONET/SDH ADMs that use CLNS based applications for management. For ISPnetworks, the local AFI (49) would just be fine! Why?
28© 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE
4. IS-IS Link State Database4. IS-IS Link State Database
• Link State Packets
• Sequence Number Packets
• More on IS- IS Metrics
• Flooding
• Database Parameters, Flags and Timers
• SPF Algorithm
29© 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE
IS-IS LS DatabaseIS-IS LS DatabaseLink State PacketsLink State Packets
LSP: RTC.00-00
RTD.
LSP: RTE.00-00
RTC
RTE
LSP: RTA.00-00
RTA
LSP: RTD.00-00
RTB.
LSP: RTB.00-00
30© 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE
IS-IS LS DatabaseIS-IS LS Database IS-IS Packet FormatIS-IS Packet Format
• A Fixed Header Contains generic packet information and other specific information about the packet
• Type, Length, Value (TLV) FieldsTLVs are blocks of specific routing-related information in IS-IS packets
IS-IS Packets are made of the following:
31© 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE
IS-IS LS DatabaseIS-IS LS Database Generic Packet FormatGeneric Packet Format
Intra-domain Routing Protocol Discriminator
Length Indicator
TLV Fields
Version/Protocol ID Extension
ID Length
R R R PDU Type
Version
Reserved
Maximum Area Addresses
Packet-Specific Header Fields
No. of Octets
1
1
1
1
1
1
1
1
32© 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE
IS-IS LS DatabaseIS-IS LS Database
LSP FormatLSP Format
Intradomain Routing Proto Descriminator
Lenth Indicator
Version/Protocol ID Extension
ID Length
PDU TypeR R R
Version
Reserved
Maximum Area Addresses
PDU Length
Remaining Lifetime
LSP ID
Sequence Number
Checksum
LSPDBOL IS TypeP ATT
TYPE LENGTH VALUE FIELDS
Octets
1
1
1
1
111
1
2
2
ID Length + 2
4
2
1
Variable
33© 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE
IS-IS LS DatabaseIS-IS LS Database LS Packet Identifier (LSPID)LS Packet Identifier (LSPID)
00c0.0040.abcd.02-01Sys ID PSN
IDLSPNo.
• Sys ID - System ID of IS or DIS in case of PSN LSP.
• PSN ID - Zero for Non-PSN LSP and Non-zero for PSN LSP
• LSP Number - Fragmentation number
34© 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE
Complete Sequence Number Packets Complete Sequence Number Packets (CSNPs)(CSNPs)
• Describes all known LSPs in the LS Database
• Standard IS-IS packet format
Fixed Header and
TLV Fields
• Each TLV includes the following info about each known LSP:
LSP ID
Remaining Lifetime
Sequence number
Checksum
35© 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE
Partial Sequence Number PacketsPartial Sequence Number Packets (PSNPs)(PSNPs)
• PSNPs are similarly constructed as CSNPs but have summaries of only specific LSPs
• PSNPs are used in 2 ways: – To acknowledge receipt of LSP on pt-to-pt links
– To request transmission of the latest version of an LSP
36© 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE
Level-1 TLVsLevel-1 TLVs
Area Address
Intermediate System Neighbors
End System Neighbors
Authentication information
IP Internal Reachability Information
Protocols Supported
IP Interface Address
TLV Name Type Origin
1
2
3
10
128129
132
ISO 10589
RFC 1195
RFC 1195
RFC 1195
ISO 10589
ISO 10589
ISO 10589
37© 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE
Level-2 TLVsLevel-2 TLVs
Area Address
Intermediate System Neighbors
Partition Designated Level-2 IS
Authentication information
IP Internal Reachability Information
Protocols Supported
IP Interface Address
TLV Name Type Origin12
4
10
128129
132
ISO 10589
RFC 1195
RFC 1195
RFC 1195
ISO 10589
ISO 10589
ISO 10589
5Prefix Neighbors ISO 10589
IP External Reachability Information 130 RFC 1195
Inter-domain Routing Protocol Information 131 RFC 1195
38© 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE
New TLVsNew TLVs
Extended IS Reachability Information
Router-Id
Extended IP Reachability Information
Dynamic Hostname Information
TLV Name Type Comments
22
134
135
137
TE Extension. Replaces TLV 2
TE Extension
TE extension used in place ofTLV 128 or 130
For dynamic distribution ofHostname to NET mapping via LSP Flooding
Point-to-Point Adjacency State 240 Reliable Pt-to-pt adjacency formation
39© 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE
Old IS-IS Old IS-IS MetricsMetrics
• ISO 10589 specifies 4 metric types Default - Supported by all routers.
Delay - measures transit delay
Expense - Measures the monetary cost of link utilization
Error - measures error probability
• Default metric type must be supported by all implementations
• Other metric types specified for QoS routing. Not supported in Cisco IOS and most other vendor implementations
40© 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE
Old IS-IS MetricsOld IS-IS Metrics
• Metric Information is carried in the following TLVs:
IS Neighbors
ES Neighbors
Prefix Neighbors
IP Internal Reachability
IP External Reachability
Extended IP Reachability
Extended IS Reachability
41© 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE
Old IS-IS MetricsOld IS-IS Metrics
• Maximum metric per interface is 63
• Maximum path metric is 1023
• There is no automatic assignment based on interface bandwidth
• Cisco uses default of 10 on all interfaces regardless of bandwidth
0
S
S
S
I/E
I/EI/E
I/E
Default Metric (6 bits)
Delay Metric
Expense Metric
Error Metric
1
Byte(s)
1
1
1
IP Address
Subnet Mask
4
4
42© 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE
Flooding and LSDB Flooding and LSDB synchronizationsynchronization
• Acknowledgement-based reliable mechanism on pt-to-point links
• Flooding on broadcast links depends on periodic advertisements of CSNPs for reliable flooding and synchronization
43© 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE
SRM and SSN FlagsSRM and SSN Flags
• Send Routing Message flag (SRMflag) and Send Sequence Number flag (SSNflag) are used by the Update Process to control delivery and acknowledgement of LSPs
SRMFlag - If set for a LSP on a specific link, indicates the LSP should be flooded on that link
SSNFlag - If set for a LSP on a link, means send a PSNP over that link to acknowledge receipt of LSP
.
44© 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE
Flooding on Pt-to-pt linksFlooding on Pt-to-pt links
RTA RTB RTC
Interface 1
Interface 2 Interface 3
Interface 4
PSNPRTA.00-00SEQ#100
PSNPRTA.00-00SEQ#100
LSPRTA.00-00SEQ#100
LSPRTA.00-00SEQ#100
45© 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE
Flooding on Broadcast LinksFlooding on Broadcast Links
RTA (DIS)RTB
PSNPRTX.00-00
SEQ#1
LSPRTX.00-00
SEQ#1
RTC
CSNPRTA.00RTB.00RTC.00RTX.00
RTA
RTB
RTA
RTX
PSNPRTX.00-00
SEQ#1
RTC
LSPRTX.00-00
SEQ#1
RTA
X
LSPRTX.00-00
SEQ#1
RTX
PSNPRTX.00-00
SEQ#1
RTA
46© 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE
IS-IS Database IS-IS Database Timers Timers
Timer Default Value Cisco IOS Command
Maxage
LSP Refresh Interval
LSP Transmission Interval
LSP Retransmit Interval
CSNP Interval
1200s
900s
33ms
5s
10s
isis max-lsp-interval
isis refresh-interval
isis lsp-interval
isis retransmit-interval
isis csnp-interval
47© 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE
SPF AlgorithmSPF Algorithm
• Shortest Path First Algorithm (SPF), also known as Dijkstra (named after Dutch Mathematician) is used by link state protocols to obtain best paths through network
• Works by building shortest path tree from calculating router (root) to all destinations in the network
• SPF Process runs over level-1 and level-2 databases separately
48© 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE
SPF AlgorithmSPF Algorithm
• In default mode, SPF process runs no frequent than every 5s
• Full SPF is run when topology changes
• When leaf elements such as IP prefixes change, routing table is adjusted with Partial Route Calculation (PRC)
• PRC evaluates only routes that changed hence less CPU intensive and relatively fast
49© 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE
SPF AlgorithmSPF Algorithm
• Duration of SPF depends on many factors such as:
Number of nodes
Number of links
Number of IP prefixes
Degree of mesh (especially for NBMA)
Speed of Route Processor
50© 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE
5. IS-IS Extensions for MPLS TE5. IS-IS Extensions for MPLS TE
• Wide Metrics
• Extended IS Reachability Information
• Extended IP Reachability Information
• Sub TLVs
• Wide Metrics
• Extended IS Reachability Information
• Extended IP Reachability Information
• Sub TLVs
51© 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE
Extended IS Reachability Information
Extended IP Reachability Information
TLV Name Type Comments
22
135
TE Extension to replace TLV 2
TE extension to IS-IS, usedin place of TLV 128 or 130
IS-IS Extensions for MPLS TEIS-IS Extensions for MPLS TEWide MetricWide Metric
• Traffic engineering extensions to IS-IS introduces reuse fields for non-implemented QoS metrics for larger Default metric values in TLV 22 and TLV 135
• 3 byte metric field in TLV 22
• 4 byte metric field in TLV 135
52© 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE
IS-IS Extensions for MPLS TEIS-IS Extensions for MPLS TETLVs 22TLVs 22
• Type (1 byte): 22
• Length (1 byte): Total Length of Value Field
• Value:
3 bytes default metric information
7 bytes of system ID + pseudonode number
1 byte of length of sub-TLVs
0-244 bytes of sub-TLVs
53© 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE
IS-IS Extensions for MPLS TEIS-IS Extensions for MPLS TETLVs 135TLVs 135
• Type (1 byte): 135
• Length (1 byte): Total Length of Value Field
• Value:
4 bytes default metric information
1 byte of control information
1 bit up/down status
1 bit sub-TLV presence indication
6 bits prefix length
0-4 bytes of IPV4 Prefix
0-250 bytes of optional sub-TLVs
1 byte to specify length of sub-TLVs
0-249 bytes of sub-TLVs
54© 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE
IS-IS Extensions for MPLS TE IS-IS Extensions for MPLS TE Sub-TLVsSub-TLVs
Administrative Group ( color )
IPV4 Interface Address
Sub-TLV Name Type Length (bytes)
3
6
IPV4 Neighbor Address
• Sub-TLVs are used to flood MPLS TE resource information and link attributes
Maximum Link Bandwidth
Reservable Link Bandwidth
Unreserved Link Bandwidth
8
9
10
11
4
4
4
4
4
32
55© 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE
6. ISP Network Design 6. ISP Network Design ConsiderationsConsiderations
• Sub-Optimal Level 1 Routing
• 2 Layer Domain-wide Prefix distribution
• Running IS-IS over NBMA
• Routing Convergence
• Sub-Optimal Level 1 Routing
• 2 Layer Domain-wide Prefix distribution
• Running IS-IS over NBMA
• Routing Convergence
56© 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE
ISP Network Design ConsiderationsISP Network Design ConsiderationsSub-optimal level-1 routingSub-optimal level-1 routing
• IS - IS Areas in 1142 and RFC 1195 are stubs.
• No inter-area routes leaked from L-1-2
• L-1 routers point default to nearest L-1-2 router based on attach bit set in L-1 LSP by level-1-2 routers
57© 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE
ISP Network Design ConsiderationsISP Network Design ConsiderationsSub-optimal level-1 routingSub-optimal level-1 routing
• RTA points default towards RTC because it is closer
• Nearest L2 Router may not be best path out
Area 49.001 Area 49.0002Backbone
10
10
10
RTA
RTFRTE
RTB
RTD
RTC
OC48
OC12
L1
L1
L1L2
L1L2
L1L2 L1
58© 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE
ISP Network Design ConsiderationsISP Network Design ConsiderationsSub-optimal level-1 routingSub-optimal level-1 routing
• Workaround is to put every router into single area and run level-1 or level-2 routing
• Make every router level-1 or level-2 only. By default Cisco routers come up as level-1-2
Area 49.001
10
10
10
RTA
RTFRTE
RTB
RTD
RTC
OC48
OC12
L2
L2
L2
L2
L2 L2
59© 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE
ISP Network Design ConsiderationsISP Network Design ConsiderationsDomain Wide Prefix DistributionDomain Wide Prefix Distribution
• AKA Route Leaking
• Allows L-1-2 routers to advertise inter-area routes into L1
• L1 routers can then determine optimal paths for destinations in other areas
• Allows scaling IS-IS networks by building hierarchy into network architecture
• draft-ietf-isis-domain-wide-02.txt
60© 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE
ISP Network Design ConsiderationsISP Network Design ConsiderationsMesh-groupMesh-group
• Configure RTA, RTB,RTC, RTD into mesh-group to reduce redundant flooding. RTE on Redundant path
• LSPs received from a member of mesh-group will be flooded to only non-members
• draft-balya-parker-mesh-00.txt
RTA
RTC
RTB
RTD
RTE
61© 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE
ISP Network Design ConsiderationsISP Network Design ConsiderationsRouting ConvergenceRouting Convergence
• Current networks configured for stability and decent convergence
• Optimizing for faster convergence desirable given improved quality of optical links
• Risks in case of unexpected instabilitiesConstant LSP regeneration
Extra Flooding
Processor intensive SPF runs, etc
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ISP Network Design ConsiderationsISP Network Design ConsiderationsRouting ConvergenceRouting Convergence
• Challenges with SPF reduced by PRC
• Redundant flooding can be alleviated with mesh-groups
• Distributed or separate forwarding engines should take load off Route Processors
• Above gains have been leveraged to improve routing convergence in some versions of Cisco IOS.
• How? By using small hold-downs and short interval between SPF runs and intelligent stabilization algorithms in case of persistent churns
• Enhancements in Cisco IOS 12.1 provide 8x faster convergence than current 12.0S releases for large networks of the order of 1000s
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7. Configuring IS-IS on Ciscos7. Configuring IS-IS on Ciscos
• Basic Configuration
• Multi-point configuration (ATM and FR)
• Typical ISP router configuration
• Default route
• Redistribution and Summarization
• MPLS TE Configuration
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Basic Configuration Basic Configuration
.6.5 198.168.1.4/30
GSR1GSR4
Pos1/0 Pos1/0
GSR212.1.1.0/24
.2.8
hostname GSR2clns routing!interface Loopback0 ip address 13.1.1.2 255.255.255.0 ip router isis SJ
interface Ethernet0 ip address 12.1.1.2 255.255.255.0 ip router isis SJ!interface POS2/0 ip address 10.1.1.1 255.255.255.252 ip router isis SJ!router isis SJ net 49.0001.0000.0000.0002.00!clns host GSR1 49.0001.0000.0000.0008.00
hostname GSR4clns routing!interface Loopback0 ip address 13.1.1.2 255.255.255.0 ip router isis SJ!interface POS2/0 ip address 10.1.1.2 255.255.255.0 ip router isis SJ!router isis SJ net 49.0002.0000.0000.0004.00
e0
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Verifying OperationVerifying Operation show clns neighborsshow clns neighbors
GSR2#show clns neighbors
System Id Interface SNPA State Holdtime Type ProtocolGSR1 Et0 00d0.58eb.d601 Up 8 L1L2 IS-ISGSR4 PO2/0 *HDLC* Up 25 L2 IS-IS
GSR2#show clns neighbors detail
System Id Interface SNPA State Holdtime Type ProtocolGSR1 Et0 00d0.58eb.d601 Up 9 L1L2 IS-IS Area Address(es): 49.0001 IP Address(es): 12.1.1.8* Uptime: 00:08:57 GSR4 PO2/0 *HDLC* Up 24 L2 IS-IS Area Address(es): 49.0002 IP Address(es): 10.1.1.2* Uptime: 00:24:08
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Verifying operationVerifying operation show clns interfaceshow clns interface
GSR2#sh clns interface pos2/0POS2/0 is up, line protocol is up Checksums enabled, MTU 4470, Encapsulation HDLC ERPDUs enabled, min. interval 10 msec. RDPDUs enabled, min. interval 100 msec., Addr Mask enabled Congestion Experienced bit set at 4 packets CLNS fast switching disabled CLNS SSE switching disabled DEC compatibility mode OFF for this interface Next ESH/ISH in 43 seconds Routing Protocol: IS-IS Circuit Type: level-1-2 Interface number 0x0, local circuit ID 0x100 Level-1 Metric: 10, Priority: 64, Circuit ID: GSR4.00 Number of active level-1 adjacencies: 0 Level-2 Metric: 10, Priority: 64, Circuit ID: GSR2.00 Number of active level-2 adjacencies: 1 Next IS-IS Hello in 2 seconds
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Verifying operationVerifying operation show clns interfaceshow clns interface
GSR2#sh clns interface e0Ethernet0 is up, line protocol is up Checksums enabled, MTU 1497, Encapsulation SAP ERPDUs enabled, min. interval 10 msec. RDPDUs enabled, min. interval 100 msec., Addr Mask enabled Congestion Experienced bit set at 4 packets CLNS fast switching disabled CLNS SSE switching disabled DEC compatibility mode OFF for this interface Next ESH/ISH in 4 seconds Routing Protocol: IS-IS Circuit Type: level-1-2 Interface number 0x1, local circuit ID 0x1 Level-1 Metric: 10, Priority: 64, Circuit ID: GSR1.01 Number of active level-1 adjacencies: 1 Level-2 Metric: 10, Priority: 64, Circuit ID: GSR1.01 Number of active level-2 adjacencies: 1 Next IS-IS LAN Level-1 Hello in 3 seconds Next IS-IS LAN Level-2 Hello in 5 seconds
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Verifying operationVerifying operation show clns protocolshow clns protocol
GSR2#sh clns protocolIS-IS Router: SJ System Id: 0000.0000.0002.00 IS-Type: level-1-2 Manual area address(es): 49.0001 Routing for area address(es): 49.0001 Interfaces supported by IS-IS: Loopback0 - IP Ethernet0 - IP POS2/0 - IP Redistributing:static Distance: 110 RRR level: none Generate narrow metrics: level-1-2 Accept narrow metrics: level-1-2 Generate wide metrics: none Accept wide metrics: none
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Verifying OperationVerifying Operation show isis topologyshow isis topology
GSR2#sh isis topology
IS-IS paths to level-1 routersSystem Id Metric Next-Hop Interface SNPAGSR2 --GSR1 10 GSR1 Et0 00d0.58eb.d601
IS-IS paths to level-2 routersSystem Id Metric Next-Hop Interface SNPAGSR2 --GSR4 10 GSR4 PO2/0 *HDLC*GSR1 10 GSR1 Et0 00d0.58eb.d601
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Verifying OperationVerifying Operationshow isis database level-n detail <lspid>show isis database level-n detail <lspid>
GSR2#show isis database level-1 detail GSR2.00-00
IS-IS Level-1 LSP GSR2.00-00LSPID LSP Seq Num LSP Checksum LSP Holdtime ATT/P/OLGSR2.00-00 * 0x0000000E 0xDAE4 1197 1/0/0 Area Address: 49.0001 NLPID: 0xCC Hostname: GSR2 IP Address: 13.1.1.2 Metric: 10 IP 12.1.1.0 255.255.255.0 Metric: 10 IP 10.1.1.0 255.255.255.252 Metric: 10 IP 13.1.1.2 255.255.255.255 Metric: 10 IS GSR2.02 Metric: 10 IS GSR1.01 Metric: 0 ES GSR2
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Verifying OperationVerifying Operationshow isis database level-n detail <lspid>show isis database level-n detail <lspid>
GSR2#show isis database level-2 detail GSR2.00-00
IS-IS Level-2 LSP GSR2.00-00LSPID LSP Seq Num LSP Checksum LSP Holdtime ATT/P/OLGSR2.00-00 * 0x0000000E 0x08B5 986 0/0/0 Area Address: 49.0001 NLPID: 0xCC Hostname: GSR2 IP Address: 13.1.1.2 Metric: 10 IS GSR2.02 Metric: 10 IS GSR1.01 Metric: 10 IS GSR4.00 Metric: 10 IP 10.1.1.0 255.255.255.252 Metric: 10 IP 12.1.1.0 255.255.255.0 Metric: 10 IP 13.1.1.2 255.255.255.255
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Verifying OperationVerifying Operationshow isis database level-n detail <lspid>show isis database level-n detail <lspid>
GSR2#sh isis dat level-1 detail GSR1.01-00
IS-IS Level-1 LSP GSR1.01-00LSPID LSP Seq Num LSP Checksum LSP Holdtime ATT/P/OLGSR1.01-00 0x00000007 0xAF8E 616 0/0/0 Metric: 0 IS GSR1.00 Metric: 0 IS GSR2.00
• Pseudonode LSP (GSR1.01-00) is generated by GSR1 which is DIS on ethernet0 of GSR2
• PSN LSP Lists all known routers connected to LAN
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Verifying OperationVerifying Operationshow ip route [isis]show ip route [isis]
GSR2#sh ip routeCodes: C - connected, S - static, i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, ia - IS-IS inter area
10.0.0.0/30 is subnetted, 1 subnetsC 10.1.1.0 is directly connected, POS2/0 12.0.0.0/24 is subnetted, 1 subnetsC 12.1.1.0 is directly connected, Ethernet0 13.0.0.0/32 is subnetted, 3 subnetsi L1 13.1.1.8 [115/20] via 12.1.1.8, Ethernet0i L2 13.1.1.4 [115/20] via 10.1.1.2, POS2/0
C 13.1.1.2 is directly connected, Loopback0
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ATM Multi-pt ConfigurationATM Multi-pt ConfigurationGSR4
.3 .410.1.1.0/24
GSR3
hostname GSR3!clns routing!interface ATM6/0.1 multipoint ip address 10.1.1.3 255.255.255.0 no ip directed-broadcast ip router isis atm pvc 1 0 8 aal5snap map-group GSR_Lab!router isis net 49.0001.0000.0000.0003.00 is-type level-2-only!map-list GSR_Lab ip 10.1.1.4 atm-vc 1 broadcast clns 49.0001.0000.0000.0004.00 atm-vc 1 broadcast
hostname GSR4!clns routing!interface ATM6/0.1 multipoint ip address 10.1.1.4 255.255.255.0 no ip directed-broadcast ip router isis atm pvc 1 0 8 aal5snap map-group GSR_Lab!router isis net 49.0001.0000.0000.0004.00 is-type level-2-only!map-list GSR_Lab ip 10.1.1.3 atm-vc 1 broadcast clns 49.0001.0000.0000.0003.00 atm-vc 1 broadcast
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ATM Multi-pt ConfigurationATM Multi-pt Configuration
GSR3#sh clns neighbors
System Id Interface SNPA State Holdtime Type ProtocolGSR4 AT6/0.1 VC 1 Up 7 L2 IS-IS
GSR3#show clns int atm6/0.1ATM6/0.1 is up, line protocol is up Checksums enabled, MTU 4467, Encapsulation ATM ERPDUs enabled, min. interval 10 msec. RDPDUs enabled, min. interval 100 msec., Addr Mask enabled Congestion Experienced bit set at 4 packets CLNS fast switching disabled CLNS SSE switching disabled DEC compatibility mode OFF for this interface Next ESH/ISH in 8 seconds Routing Protocol: IS-IS Circuit Type: level-1-2 Interface number 0x0, local circuit ID 0x1 Level-2 Metric: 10, Priority: 64, Circuit ID: GSR4.01 Number of active level-2 adjacencies: 1 Next IS-IS LAN Level-2 Hello in 7 seconds
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ATM Pt-to-pt ConfigurationATM Pt-to-pt ConfigurationGSR4
.3 .410.1.1.0/24
GSR3
hostname GSR4!clns routing! interface ATM6/0.2 point-to-point ip address 192.168.1.2 255.255.255.252 no ip directed-broadcast ip router isis atm pvc 2 0 10 aal5snap!router isis net 49.0001.0000.0000.0004.00 is-type level-2-only
hostname GSR3!clns routing!interface ATM6/0.2 point-to-point ip address 192.168.1.1 255.255.255.252 no ip directed-broadcast ip router isis atm pvc 2 0 10 aal5snap!router isis net 49.0001.0000.0000.0003.00 is-type level-2-only
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ATM Point-pt ConfigurationATM Point-pt Configuration
GSR3#show clns neighbors
System Id Interface SNPA State Holdtime Type ProtocolGSR4 AT6/0.2 VC 2 Up 26 L2 IS-ISGSR4 AT6/0.1 VC 1 Up 9 L2 IS-IS
GSR3#show clns int atm6/0.2ATM6/0.2 is up, line protocol is up Checksums enabled, MTU 4467, Encapsulation ATM ERPDUs enabled, min. interval 10 msec. RDPDUs enabled, min. interval 100 msec., Addr Mask enabled Congestion Experienced bit set at 4 packets CLNS fast switching disabled CLNS SSE switching disabled DEC compatibility mode OFF for this interface Next ESH/ISH in 16 seconds Routing Protocol: IS-IS Circuit Type: level-1-2 Interface number 0x1, local circuit ID 0x100 Level-2 Metric: 10, Priority: 64, Circuit ID: GSR3.00 Number of active level-2 adjacencies: 1 Next IS-IS Hello in 3 seconds
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Frame Relay Multi-pt ConfigurationFrame Relay Multi-pt Configuration
RTA RTB
hostname RTA!clns routing!interface Serial0 ip address 192.168.1.1 255.255.255.0 ip router isis encapsulation frame-relay frame-relay map clns 200 broadcast frame-relay map ip 192.168.1.2 200!router isis net 49.0002.0000.0000.0001.00 is-type level-2-only
Hostname RTB!clns routing!interface Serial0 ip address 192.168.1.2 255.255.255.0 ip router isis isp encapsulation frame-relay frame-relay map clns 200 broadcast frame-relay map ip 192.168.1.1 200!router isis net 49.0001.0000.0000.0002.00 is-type level-2-only
FR CLOUD.1 .2
192.168.1.0/24
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Typical ISP Router ConfigurationTypical ISP Router Configuration
GSR1#interface Loopback0ip address 172.160.250.1 255.255.255.255!interface POS1/0ip address 192.168.1.1 255.255.255.0isis metric 100 level-2isis hello-interval 12 level-2isis hello-multiplier 5 level-2isis retransmit-interval 100!router isis SJsummary-address 172.160.0.0 255.255.0.0 passive-interface Loopback0distance 15 ipnet 49.0001.0001.0000.0001.0002.0001.1721.6025.0001.00is-type level-2-onlymetric-style widespf-interval 30log-adjacency-changes
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default-information originatedefault-information originate
RTB#sh isis database RTE.00-00 detail level-2 IS-IS Level-2 LSP RTE.00-00LSPID LSP Seq Num LSP Checksum LSP Holdtime ATT/P/OLRTE.00-00 * 0x0000008D 0xDBD0 848 0/0/0 Area Address: 49.0002 NLPID: 0x81 0xCC IP Address: 172.16.2.2 Metric: 10 IS RTE.01 Metric: 10 IS RTB.00 Metric: 0 IP-External 0.0.0.0 0.0.0.0 Metric: 20 IP 172.16.5.16 255.255.255.252 Metric: 20 IP 172.16.5.12 255.255.255.252 Metric: 10 IP 172.16.5.4 255.255.255.252 Metric: 10 IP 172.16.2.0 255.255.255.0
Hostname RTE!router isis SJ default-information originate net 49.0002.0000.0000.0002.00!
Used for originating default into level-2Level-1 routers automatically point default to nearest level-2 router based on attach bit information
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Verifying OperationVerifying Operation show isis databaseshow isis database
GSR2#sh isis databaseIS-IS Level-1 Link State DatabaseLSPID LSP Seq Num LSP Checksum LSP Holdtime ATT/P/OLGSR2.00-00 * 0x00000008 0x7399 716 1/0/0GSR1.00-00 0x00000002 0x7307 545 1/0/0GSR1.01-00 0x00000003 0xB78A 574 0/0/0
IS-IS Level-2 Link State DatabaseLSPID LSP Seq Num LSP Checksum LSP Holdtime ATT/P/OLGSR2.00-00 * 0x00000009 0xC049 1054 0/0/0GSR4.00-00 0x00000009 0x71D6 999 0/0/0GSR1.00-00 0x0000626A 0x1963 701 0/0/0GSR1.01-00 0x0000696F 0x32C2 906 0/0/0
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SummarizationSummarization
.6.5
172.16.5.0/30RTB RTE
172.170.1.0/24
hostname RTB!interface Ethernet0 ip address 172.170.1.1 255.255.255.0 ip router isis SJ!router isis SJ summary-address 172.170.0.0 255.255.0.0 net 49.0001.0000.0000.0001.00
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SummarizationSummarization
RTE#sh ip routeGateway of last resort is not set i L2 172.170.0.0/16 [115/20] via 172.16.5.5, Serial 0
172.16.0.0/16 is subnetted, 1 subnets
C 172.16.5.4/30 is directly connected, Serial0
RTB#sh isis dat RTB.00-00 l2 detailIS-IS Level-2 LSP RTB.00-00LSPID LSP Seq Num LSP Checksum LSP Holdtime ATT/P/OLRTB.00-00 * 0x00000096 0x86F6 877 0/0/0 Area Address: 49.0001 NLPID: 0x81 0xCC IP Address: 172.170.1.1 Metric: 10 IS RTB.02 Metric: 10 IS RTE.00 Metric: 10 IS RTF.00 Metric: 10 IP 172.16.5.4 255.255.255.252 Metric: 10 IP 172.170.0.0 255.255.0.0
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RedistributionRedistribution
.6.5
172.16.5.0/30RTB RTE
172.170.1.0/24
RTG
IS-IS DomainOSPF Domain
172.80.1.1/24
RTErouter ospf 1 network 172.16.2.0 0.0.0.255 area 0!router isis SJ redistribute ospf 1 metric 20 metric-type internal level-2 net 49.0002.0000.0000.0002.00
172.16.2.0/24
.3 .4
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RedistributionRedistribution
RTE#sh isis dat rte.00-00 level-2 detail IS-IS Level-2 LSP RTE.00-00LSPID LSP Seq Num LSP Checksum LSP Holdtime ATT/P/OLRTE.00-00 * 0x000003B3 0x66A7 859 0/0/0 Area Address: 49.0002 NLPID: 0x81 0xCC IP Address: 172.16.2.2 Metric: 10 IS RTE.01 Metric: 10 IS RTB.00 Metric: 20 IP-External 172.180.0.0 255.255.0.0 Metric: 20 IP 172.16.5.16 255.255.255.252 Metric: 20 IP 172.16.5.12 255.255.255.252 Metric: 10 IP 172.16.5.4 255.255.255.252 Metric: 10 IP 172.16.2.0 255.255.255.0
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MPLS TE ConfigurationMPLS TE Configuration
GSR1GSR4
GSR6
GSR2
Pos 2/0
Pos 3/0
Pos 2/0
Eth 0Eth 0
Pos 2/2 Pos 4/0
Pos 4/0
10.1.1.0/30
12.1.1.0/30
10.1.1.4/3010.1.1.8/30
.8.2
.5
.6
.4.1
.9
.10
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MPLS TE ConfigurationMPLS TE ConfigurationIS-IS configurationIS-IS configuration
hostname GSR2!mpls traffic-eng tunnelsinterface Loopback0 ip address 13.1.1.2 255.255.255.255 no ip directed-broadcast ip router isis SJ!interface POS2/0 ip address 10.1.1.1 255.255.255.252 ip router isis SJ mpls traffic-eng tunnels isis metric 100 level-2 ip rsvp bandwidth 10000 10000!interface POS3/0 ip address 10.1.1.9 255.255.255.252 ip router isis SJ mpls traffic-eng tunnels isis metric 100 level-2
ip rsvp bandwidth 10000 10000!router isis SJ net 49.0001.0000.0000.0002.00 is-type level-2-only metric-style wide log-adjacency-changes mpls traffic-eng router-id Loopback0 mpls traffic-eng level-2 !
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MPLS TE ConfigurationMPLS TE ConfigurationDynamic Path Dynamic Path
hostname GSR2!
interface Tunnel1 ip unnumbered Loopback0 no ip directed-broadcast tunnel destination 13.1.1.4 tunnel mode mpls traffic-eng tunnel mpls traffic-eng autoroute announcetunnel mpls traffic-eng bandwidth 10000 tunnel mpls traffic-eng path-option 1 dynamic
• Tunnel is configured on head end router
• For dynamic path discovery, dynamic path option is used
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MPLS TE ConfigurationMPLS TE ConfigurationExplicit Path Explicit Path
hostname GSR2!
interface Tunnel2 ip unnumbered Loopback0 no ip directed-broadcast tunnel destination 13.1.1.4 tunnel mode mpls traffic-eng tunnel mpls traffic-eng autoroute announce tunnel mpls traffic-eng path-option 1 explicit name ViaGSR6! ip explicit-path name ViaGSR6 enable next-address 13.1.1.6 next-address 13.1.1.4!ip route 192.168.5.0 255.255.255.0 Tunnel2
• Tunnel is configured on head end router
• Explicit path defined
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MPLS TE ConfigurationMPLS TE Configuration
GSR2#show mpls traffic-eng tunn briefSignalling Summary: LSP Tunnels Process: running RSVP Process: running Forwarding: enabled Periodic reoptimization: every 3600 seconds, next in 1180 secondsTUNNEL NAME DESTINATION STATUS STATEGSR2_t1 13.1.1.4 up upGSR2_t2 13.1.1.4 up upDisplayed 2 (of 2) heads, 0 (of 0) midpoints, 0 (of 0) tails
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MPLS TE ConfigurationMPLS TE ConfigurationGSR2#sh mpls traffic-eng tunnels name GSR2_t1 Name: GSR2_t1 (Tunnel1) Destination: 13.1.1.4 Status: Admin: up Oper: up Path: valid Signalling: connected
path option 1, type dynamic (Basis for Setup, path weight 100)Config Paramters: Bandwidth: 1000 Priority: 7 7 Affinity: 0x0/0xFFFF AutoRoute: enabled LockDown: disabled
InLabel : - OutLabel : POS2/0, implicit-null RSVP Signalling Info: Src 13.1.1.2, Dst 13.1.1.4, Tun_Id 1, Tun_Instance 1 RSVP Path Info: My Address: 13.1.1.2 Explicit Route: 10.1.1.2 13.1.1.4 Record Route: NONE Tspec: ave rate=1000 kbits, burst=1000 bytes, peak rate=1000 kbits RSVP Resv Info: Record Route: NONE Fspec: ave rate=1000 kbits, burst=1000 bytes, peak rate=Inf
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MPLS TE ConfigurationMPLS TE Configuration Tunnel1 Tunnel1
GSR2#sh mpls traffic-eng tunnels name GSR2_t1 Name: GSR2_t1 (Tunnel1) Destination: 13.1.1.4 Status: Admin: up Oper: up Path: valid Signalling: connected
path option 1, type dynamic (Basis for Setup, path weight 100)Config Paramters: Bandwidth: 1000 Priority: 7 7 Affinity: 0x0/0xFFFF AutoRoute: enabled LockDown: disabled
InLabel : - OutLabel : POS2/0, implicit-null RSVP Signalling Info: Src 13.1.1.2, Dst 13.1.1.4, Tun_Id 1, Tun_Instance 1 RSVP Path Info: My Address: 13.1.1.2 Explicit Route: 10.1.1.2 13.1.1.4 Record Route: NONE Tspec: ave rate=1000 kbits, burst=1000 bytes, peak rate=1000 kbits RSVP Resv Info: Record Route: NONE Fspec: ave rate=1000 kbits, burst=1000 bytes, peak rate=Inf
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MPLS TE ConfigurationMPLS TE Configuration Tunnel 2 Tunnel 2
GSR2#sh mpls traffic-eng tunnels name GSR2_t1 Name: GSR2_t2 (Tunnel2) Destination: 13.1.1.4 Status: Admin: up Oper: up Path: valid Signalling: connected
path option 1, type explicit ViaGSR6 (Basis for Setup, path weight 110) Config Paramters: Bandwidth: 0 Priority: 7 7 Affinity: 0x0/0xFFFF AutoRoute: enabled LockDown: disabled InLabel : - OutLabel : POS3/0, 26 RSVP Signalling Info: Src 13.1.1.2, Dst 13.1.1.4, Tun_Id 2, Tun_Instance 1 RSVP Path Info: My Address: 13.1.1.2 Explicit Route: 10.1.1.10 10.1.1.5 Record Route: NONE Tspec: ave rate=0 kbits, burst=1000 bytes, peak rate=0 kbits RSVP Resv Info: Record Route: NONE
Fspec: ave rate=0 kbits, burst=1000 bytes, peak rate=Inf
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MPLS TE ConfigurationMPLS TE Configuration show isis database verbose show isis database verbose
GSR2#show isis database verbose GSR2.00-00IS-IS Level-2 LSP GSR2.00-00LSPID LSP Seq Num LSP Checksum LSP Holdtime ATT/P/OLGSR2.00-00 * 0x00000009 0x5304 1125 0/0/0 Area Address: 49.0001 NLPID: 0xCC Hostname: GSR2 Router ID: 13.1.1.2 IP Address: 13.1.1.2 Metric: 100 IS-Extended GSR6.00 Affinity: 0x00000000 Interface IP Address: 10.1.1.9 Neighbor IP Address: 10.1.1.10 Physical BW: 622000000 bits/sec Reservable BW: 10000000 bits/sec BW Unreserved[0]: 10000000 bits/sec, BW Unreserved[1]: 10000000 bits/sec BW Unreserved[2]: 10000000 bits/sec, BW Unreserved[3]: 10000000 bits/sec BW Unreserved[4]: 10000000 bits/sec, BW Unreserved[5]: 10000000 bits/sec BW Unreserved[6]: 10000000 bits/sec, BW Unreserved[7]: 10000000 bits/sec
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MPLS TE ConfigurationMPLS TE Configuration show isis database verbose cont’d show isis database verbose cont’d
GSR2#show isis database verbose GSR2.00-00
[snip]
Metric: 100 IS-Extended GSR4.00 Affinity: 0x00000000 Interface IP Address: 10.1.1.1 Neighbor IP Address: 10.1.1.2 Physical BW: 2488000000 bits/sec Reservable BW: 10000000 bits/sec BW Unreserved[0]: 10000000 bits/sec, BW Unreserved[1]: 10000000 bits/sec BW Unreserved[2]: 10000000 bits/sec, BW Unreserved[3]: 10000000 bits/sec BW Unreserved[4]: 10000000 bits/sec, BW Unreserved[5]: 10000000 bits/sec BW Unreserved[6]: 10000000 bits/sec, BW Unreserved[7]: 9000000 bits/sec Metric: 100 IP 10.1.1.8/30 Metric: 100 IP 10.1.1.0/30 Metric: 10 IP 13.1.1.2/32
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GSR2#sh isis mpls traffic-eng ? adjacency-log Adjacency Log advertisements Agent advertisements downstream-tree MPLS TE Optimized Autoroute Calculation downstream tree tunnel Tunnel Information
GSR2#sh isis mpls traffic-eng adjacency-log IS-IS MPLS TE logWhen Neighbor ID IP Address Interface Status Level00:50:13 GSR4.00 10.1.1.2 PO2/0 Up level-200:50:12 GSR6.00 10.1.1.10 PO3/0 Up level-2
GSR2#sh isis mpls traffic-eng tunnelGSR2#sh isis mpls traffic-eng tunnelSystem Id Tunnel Name Bandwidth Nexthop Metric ModeGSR4.00 Tunnel2 0 13.1.1.4 Tunnel1 1000 13.1.1.4
MPLS TE MPLS TE IS-IS show commandsIS-IS show commands
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MPLS TE ConfigurationMPLS TE Configurationhostname GSR4mpls traffic-eng tunnels!interface Loopback0 ip address 13.1.1.4 255.255.255.255 ip router isis SJ!interface Loopback5 ip address 192.168.5.1 255.255.255.0!interface Ethernet0 ip address 12.1.1.4 255.255.255.0 ip router isis SJ!interface POS2/0 ip address 10.1.1.2 255.255.255.252 ip router isis SJ mpls traffic-eng tunnelsip rsvp bandwidth 1000 1000
interface POS4/0 ip address 10.1.1.5 255.255.255.252 no ip directed-broadcast ip router isis SJ mpls traffic-eng tunnels ip rsvp bandwidth 1000 1000!router isis SJ net 49.0001.0000.0000.0004.00 is-type level-2-only metric-style wide mpls traffic-eng router-id Loopback0 mpls traffic-eng level-2
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MPLS TE ConfigurationMPLS TE Configuration
hostname GSR6!mpls traffic-eng tunnels!interface Loopback0 ip address 13.1.1.6 255.255.255.255 ip router isis SJ!interface POS4/0 ip address 10.1.1.6 255.255.255.252 no ip directed-broadcast ip router isis SJ mpls traffic-eng tunnels ip rsvp bandwidth 1000 1000
interface POS2/2 ip address 10.1.1.10 255.255.255.252 no ip directed-broadcast ip router isis SJ mpls traffic-eng tunnels ip rsvp bandwidth 1000 1000
router isis SJ net 49.0001.0000.0000.0006.00 is-type level-2-only metric-style wide mpls traffic-eng router-id Loopback0 mpls traffic-eng level-2
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MPLS TE ConfigurationMPLS TE Configurationshow ip routeshow ip route
GSR2#sh ip routeCodes: C - connected, S - static, i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2ia - IS-IS inter area Gateway of last resort is not set S 192.168.5.0/24 is directly connected, Tunnel2 10.0.0.0/30 is subnetted, 3 subnetsC 10.1.1.8 is directly connected, POS3/0C 10.1.1.0 is directly connected, POS2/0i L2 10.1.1.4 [115/20] via 10.1.1.10, POS3/0 [115/20] via 13.1.1.4, Tunnel2 12.0.0.0/24 is subnetted, 1 subnetsi L2 12.1.1.0 [115/20] via 13.1.1.4, Tunnel2 13.0.0.0/32 is subnetted, 3 subnetsi L2 13.1.1.4 [115/20] via 13.1.1.4, Tunnel2i L2 13.1.1.6 [115/20] via 10.1.1.10, POS3/0C 13.1.1.2 is directly connected, Loopback0
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8. Basic Troubleshooting8. Basic Troubleshooting
• Show Commands
• Debugging Commands
• Error logs
• MPLS TE troubleshooting
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TroubleshootingTroubleshootingCLNS CommandsCLNS Commands
show clns intshow clns protocol show clns neighbors detail show clns is-neighborsshow clns es-neighborsshow clns routeshow clns cacheshow clns traffic
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Troubleshooting Troubleshooting show isis commandsshow isis commands
show isis spf-logshow isis database detailshow isis database<lspid>show isis route show isis database L1|L2
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Troubleshooting Troubleshooting Debugging CommandsDebugging Commands
debug clns:events CLNS error eventsfilters CLNS filterspackets CLNS packet switching activityrouting CLNS routing table activity
debug isis:adj-packets IS-IS Adjacency related packetschecksum-errors IS-IS LSP checksum errorslocal-updates IS-IS local update packetssnp-packets IS-IS CSNP/PSNP packetsspf-events IS-IS Shortest Path First Eventsspf-statistics IS-IS SPF Timing and Statistic Dataspf-triggers IS-IS SPF triggering eventsupdate-packets IS-IS Update related packet
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TroubleshootingTroubleshooting Error Logging Error Logging
log-adjacency-changes CommandUsed to keep track of changes in the state of adjacent neighbors
Helpful in tracking connectivity problems
RTX#show log
%CLNS-5-ADJCHANGE: ISIS: Adjacency to 0000.0000.0001 (ethernet 0)
%CLNS-5-ADJCHANGE: ISIS: Adjacency to 0000.0000.0002 (ethernet 0)
BAD Clns Packet ErrorsNov 16 02:18:04.848 EDT: %CLNS-4-BADPACKET: ISIS: P2P hello, option 8 length 53 remaining bytes (51) from VC 2 (ATM4/0.2)Nov 16 02:18:04.848 EDT: ISIS: P2P hello, option 8 length 53 > remaining bytes (51) from VC 2 (ATM4/0.2)
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TroubleshootingTroubleshootingSPF LogsSPF Logs
RTB#sh isis spf-logLevel 1 SPF logWhen Duration Nodes Count Triggers00:25:27 8 4 1 PERIODIC00:18:09 12 5 2 NEWLSP TLVCONTENT00:10:27 8 5 1 PERIODIC
Level 2 SPF logWhen Duration Nodes Count Triggers00:40:35 8 3 1 PERIODIC00:25:35 8 3 1 PERIODIC00:18:17 8 3 1 TLVCONTENT00:10:34 8 3 1 PERIODIC
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TroubleshootingTroubleshootingMPLS TE MPLS TE
• Show mpls traffic-eng tunnel
• show mpls traffic-eng topology
• show mpls traffic-eng autoroute
• show mpls traffic-eng link advertisements
• show isis traffic-eng tunnels
• show isis database [verbose|detail]
• show ip rsvp
• Debug traffic-eng path calc
• debug ip rsvp
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9. Further Reading9. Further Reading
• ISO 8473 Connectionless Network Protocol (CNLP)
• ISO 10589 ISO IS-IS Routing Protocol
• ISO 9542 ES-IS Routing Protocol
• ISO 8348/Ad2 Network Services Access Points
• RFC 1195 Integrated (Dual) IS-IS
• RFC 1237 Guidelines for OSI NSAP allocation in the Internet
• http://www.cisco.com/univercd/cc/td/doc/product/software/ios113ed/113ed_cr/np1_c/1cisis.htm
• http://www.cisco.com/univercd/cc/td/doc/product/software/ios121/121newft/121t/121t3/traffeng.htm
• ISO 8473 Connectionless Network Protocol (CNLP)
• ISO 10589 ISO IS-IS Routing Protocol
• ISO 9542 ES-IS Routing Protocol
• ISO 8348/Ad2 Network Services Access Points
• RFC 1195 Integrated (Dual) IS-IS
• RFC 1237 Guidelines for OSI NSAP allocation in the Internet
• http://www.cisco.com/univercd/cc/td/doc/product/software/ios113ed/113ed_cr/np1_c/1cisis.htm
• http://www.cisco.com/univercd/cc/td/doc/product/software/ios121/121newft/121t/121t3/traffeng.htm
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9. Further Reading9. Further Reading
• RFC Drafts:
• draft-ietf-isis-traffic-02.txt
• draft-ietf-isis-3way-01.txt
• draft-ietf-isis-domain-wide-01.txt
• draft-ietf-isis-dyname-01.txt
• draft-hsmit-mpls-igp-spf-00.txt
• draft-ietf-isis-hmac-00.txt
• RFC Drafts:
• draft-ietf-isis-traffic-02.txt
• draft-ietf-isis-3way-01.txt
• draft-ietf-isis-domain-wide-01.txt
• draft-ietf-isis-dyname-01.txt
• draft-hsmit-mpls-igp-spf-00.txt
• draft-ietf-isis-hmac-00.txt
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