ipcn2000, paris, france ©1997 british telecommunications plc edge mobility architecture alan...
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IPCN2000, Paris, France©1997 British Telecommunications plc
Edge Mobility Architecture
Alan O’Neill, BT Adastral Park
Scott Corson, University of Maryland
George Tsirtsis, BT Adastral Park
May 2000
IPCN2000, Paris, France©1997 British Telecommunications plc
Objectives• Solve IP mobile routing and fast restoration
– Homogeneous hand-over between heterogeneous technologies
– Very large-scale domains
• Why?– VoIP with high availability, real-time services – 3G migration to Internet architecture– Fixed/Mobile Convergence
IPCN2000, Paris, France©1997 British Telecommunications plc
Fixed MobileConverged Domain
Convergence - UMTS ++
Radio LAN’s
Bluetooth
Cellular Mobile
DialAccess
CorporateAccess
IPCN2000, Paris, France©1997 British Telecommunications plc
EMA Hand-over Architecture
TempTunnel
NAR
Update
Update
Hand-over? (AAA)
OAR
IPCN2000, Paris, France©1997 British Telecommunications plc
Break before Make
OAR NAR
MH
OAR NAR
MH
tunnel OAR NAR
MH
OAR NAR
MH
tunnel OAR NAR
MH
(a) before handover (b) sensing new link, build tunnel
(e) break occurs(c) inject new routing on make (d) routing converges,tear down tunnel
OAR NAR
MH
OAR NAR
MH
tunnel OAR NAR
MH
tunnel OAR NAR
MH
tunnel OAR NAR
MH
(a) before handover (b) sensing new link,build tunnel
(c) tunnel data on break (d) inject new routing on make,forward cached data (if any)
(e) routing converges,tear down tunnel
Make before Break
IPCN2000, Paris, France©1997 British Telecommunications plc
Mobile IPv6 & EMA
1. EMA
OARAAR
• AAR is CoR for MN-HA and HA for CoA• TORA MER moves CoA within domain• One CoA, Reg and BU per domain• Improved speed, reduced delay
NAR
HACN
To CoA (native or RH)
IPCN2000, Paris, France©1997 British Telecommunications plc
Inter-domain Mobile IP
1. EMA 2. OSPF
OAR NARAARSAR
Tunnels
Native
• Native forwarding in EMA domains• MIP tunnels / bindings inter-domain• MIP tunnels / bindings in OSPF domains
IPCN2000, Paris, France©1997 British Telecommunications plc
Present GPRS/UMTS
SGSN
SGSN
GGSNx
GGSNy
ISPx
ISPy
PublicAddress Allocators
Private GPRS Domain
GTPTunnelling
Local ServicesWeb hostingMulticast, QoSLocal Traffic
IPCN2000, Paris, France©1997 British Telecommunications plc
GGSNv4/v6
SGSN*AAA/DHCP RNC
RNC
DSLAM
GGSNv4/v6
Corp
ISP
IP in the RNCSGSN out of data-path
DHCP/[email protected]+Key
E.gWaveLan
xDSL
EMA DomainRouting
Local ServicesWeb hostingMulticast, QoSLocal Traffic
IPCN2000, Paris, France©1997 British Telecommunications plc
Tora -> Localization = Scalability
Handover
• no far-reaching control messages• eliminates convergence problem
IPCN2000, Paris, France©1997 British Telecommunications plc
Tora -> local decisions & loop-free
• Totally-ordered heights -> “gravity”• Packets have to go uphill to form loop
DEST
SOURCES
IPCN2000, Paris, France©1997 British Telecommunications plc
Tora Fast Restore
- Rapidly detects link/node failures
DEST
SOURCES
IPCN2000, Paris, France©1997 British Telecommunications plc
Tora Fast Restore
• immediate localized reaction •critical for premium VoIP etc
DEST
SOURCES
IPCN2000, Paris, France©1997 British Telecommunications plc
Hierarchical Mesh TopologyCR CR CR
IR IRIR IR IR
ER ER ER ER ER ER ER ER ER
AR AR AR AR AR AR AR AR AR AR AR AR AR AR AR AR AR AR AR
• CRs form full mesh (clique) at top level• IRs, ERs and ARs dual-homed for robustness• Order of magnitude increase in routers at each level (e.g. 10 CRs, 100 IRs, 1000 ERs, 10000 ARs, etc.)
IPCN2000, Paris, France©1997 British Telecommunications plc
CR CR CR
IR
ER
AR
ER
IR IR
ER
AR AR
Prefix DAG per Access Router
• Inject prefix(es) into ‘unordered’ domain from Access Router
IPCN2000, Paris, France©1997 British Telecommunications plc
Prefix DAG per Access Router
•‘Order’ all links towards each AR - aggregated DAG• DAG rooted at receiving mobile host (MH) i.• Relevant node heights with initial hop count shown
CR CR CR
IR
ER
AR
ER
IR IR
ER
AR AR(0,0,0,1,i)
(0,0,0,2,i)
(0,0,0,3,i)
(0,0,0,4,i)
(0,0,0,5,i)
(0,0,0,3,i)
(0,0,0,4,i)
(0,0,0,5,i)
(0,0,0,4,i) (0,0,0,4,i) (0,0,0,5,i)
(0,0,0,5,i)
IPCN2000, Paris, France©1997 British Telecommunications plc
IP address per active IP session
• Mobile Host (MH) wants to send / receive IP packets• Gets allocated IP address from AAR prefix
CR CR CR
IR
ER
AR
ER
IR IR
ER
AAR AR(0,0,0,1,i)
(0,0,0,2,i)
(0,0,0,3,i)
(0,0,0,4,i)
(0,0,0,5,i)
(0,0,0,3,i)
(0,0,0,4,i)
(0,0,0,5,i)
(0,0,0,4,i) (0,0,0,4,i) (0,0,0,5,i)
(0,0,0,5,i)
MH(0,0,0,0,i)
AAA
IPCN2000, Paris, France©1997 British Telecommunications plc
In-session (active) Mobility Profile
d
PD/T(d)
d
• D = geographical distance moved• T = session duration (IP address effective lifetime)• Assumption: Movement Localized (in probability)
Session begins at any Access RouterSession terminated on inactivity timer
profile is a function of T
(distance moved)
(pro
bab
ilit
y)
MH
IPCN2000, Paris, France©1997 British Telecommunications plc
Host Route InjectionCR CR CR
IR IRIR IR IR
ER ER ER ER ER ER ER ER ER
AR AR AR AR AR AR AR AR AR AR AR AR AR AR AR AR AR AR AR
MH
• Movement further from AAR deepens injection towards core
IPCN2000, Paris, France©1997 British Telecommunications plc
• Shows data flow from MH to MH via default DAG
“Make Before Break”CR CR CR
IR
ER
AR
MH
ER
IR IR
ER
AR
MH
Ongoingcall tomobile
(0,0,0,1,i)
(0,0,0,2,i)
(0,0,0,3,i)
(0,0,0,4,i)
(0,0,0,5,i)
(0,0,0,3,i)
(0,0,0,4,i)
(0,0,0,5,i)
(0,0,0,0,i)
(0,0,0,4,i) (0,0,0,4,i) (0,0,0,5,i)
(0,0,0,5,i)
AR
IPCN2000, Paris, France©1997 British Telecommunications plc
CR CR CR
IR
ER
MH
ER
IR IR
ER
MH
• Mobile senses signal but has no new link (yet)• Sends “Tunnel Initiation” (TIN) packet to old AR• Computes its new height and sends it in TIN packet
(0,0,0,1,i)
(0,0,0,2,i)
(0,0,0,3,i)
(0,0,0,4,i)
(0,0,0,5,i)
(0,0,0,3,i)
(0,0,0,4,i)
(0,0,0,5,i)
(-1,0,0,0,i)
TIN
(0,0,0,4,i) (0,0,0,4,i) (0,0,0,5,i)
(0,0,0,5,i)
AR AR AR
IPCN2000, Paris, France©1997 British Telecommunications plc
CR CR CR
IR
ER
MH
ER
IR IR
ER
MH
tunnel
•Old AR establishes tunnel link to new ARs•Sets its view of tunnel height equal to (-1,0,0,1,i)•Old AR forwards TIN packet to new AR
(0,0,0,0,i)
(0,0,0,2,i)
(0,0,0,3,i)
(0,0,0,4,i)
(0,0,0,3,i)
(0,0,0,4,i)
(0,0,0,5,i)
TIN
(0,0,0,5,i)
(-1,0,0,0,i)
(-1,0,0,1,i)
(0,0,0,4,i) (0,0,0,4,i) (0,0,0,5,i)
(0,0,0,5,i)
AR AR AR
IPCN2000, Paris, France©1997 British Telecommunications plc
CR CR CR
IR
ER
MH
ER
IR IR
ER
MH
• TIN most likely arrives and is cached.• On L2 ‘make’, generate UUPD if TIN cached, or generate when TIN or L3M arrives at new AR
(0,0,0,1,i)
(0,0,0,2,i)
(0,0,0,3,i)
(0,0,0,4,i)
(0,0,0,3,i)
(0,0,0,4,i)
(0,0,0,5,i) (0,0,0,5,i)
(-1,0,0,0,i)
(-1,0,0,1,i)
(0,0,0,4,i) (0,0,0,4,i) (0,0,0,5,i)
(0,0,0,5,i)
AR AR ARtunnel
IPCN2000, Paris, France©1997 British Telecommunications plc
CR CR CR
IR
ER
MH
ER
IR IR
ER
MH
UUPD
•Make event occurs, send UUPD•If UUPD travels fast enough, data tunnel not needed
(0,0,0,1,i)
(0,0,0,2,i)
(0,0,0,3,i)
(0,0,0,4,i)
(0,0,0,5,i)
(0,0,0,3,i)
(0,0,0,4,i)
(0,0,0,5,i)
(-1,0,0,0,i)
L3M (if mobile assist)
(0,0,0,4,i) (0,0,0,4,i) (0,0,0,5,i)
(0,0,0,5,i)
(-1,0,0,1,i)
AR AR ARtunnel
IPCN2000, Paris, France©1997 British Telecommunications plc
CR CR CR
IR
ER
MH
ER
IR IR
ER
MH
•Loss of link--old AR forwards data through tunnel•Tunnel exists to prevent TORA reaction at old AR•TORA UUPD continues propagation
(0,0,0,1,i)
(0,0,0,2,i)
(0,0,0,3,i)
(0,0,0,4,i)
(0,0,0,5,i)
(0,0,0,3,i)
(0,0,0,4,i)
(0,0,0,5,i)
(-1,0,0,0,i)
(0,0,0,4,i) (0,0,0,4,i) (0,0,0,5,i)
(0,0,0,5,i)
(-1,0,0,2,i)
(-1,0,0,1,i)
AR AR ARtunnel
IPCN2000, Paris, France©1997 British Telecommunications plc
CR CR CR
IR
ER
MH
ER
IR IR
ER
MH
•TORA update hits a crossover router
(0,0,0,1,i)
(0,0,0,2,i)
(0,0,0,3,i)
(0,0,0,4,i)
(0,0,0,5,i)
(0,0,0,3,i)
(0,0,0,4,i)
(0,0,0,5,i)
(-1,0,0,0,i)
(0,0,0,4,i) (0,0,0,4,i) (0,0,0,5,i)
(0,0,0,5,i)(-1,0,0,3,i)
(-1,0,0,2,i)
(-1,0,0,1,i)
AR AR ARtunnel
IPCN2000, Paris, France©1997 British Telecommunications plc
CR CR CR
IR
ER
MH
ER
IR IR
ER
MH
•Crossover routers re-order links and divert data•Tunnel ‘holdsdown’ TORA reaction at old AR• Tunnel state removed when UUPD hits old AR
(0,0,0,1,i)
(0,0,0,2,i)
(0,0,0,3,i)
(0,0,0,4,i)
(0,0,0,5,i)
(0,0,0,3,i)
(0,0,0,4,i)
(0,0,0,5,i)
(-1,0,0,0,i)
(-1,0,0,1,i)
(0,0,0,4,i) (0,0,0,4,i) (0,0,0,5,i)
(0,0,0,5,i)
(-1,0,0,4,i)
(-1,0,0,3,i)
(-1,0,0,2,i)
(-1,0,0,1,i)
AR AR ARtunnel
IPCN2000, Paris, France©1997 British Telecommunications plc
CR CR CR
IR
ER
MH
ER
IR IR
ER
MH
•Old AR updates height and tears down tunnel•Only (5) nodes in green have updated heights•UUPD-Ack propogates back to new AR (not shown)
(0,0,0,3,i)
(0,0,0,4,i)
(0,0,0,5,i)
(-1,0,0,0,i)
(0,0,0,4,i) (0,0,0,4,i) (0,0,0,5,i)
(0,0,0,5,i)
(-1,0,0,4,i)
(-1,0,0,3,i)
(-1,0,0,2,i)
(-1,0,0,1,i)(0,0,0,1,i)
(0,0,0,2,i)
(0,0,0,3,i)
(0,0,0,4,i)
(0,0,0,5,i)AR AR AR(-1,0,0,5,i)
IPCN2000, Paris, France©1997 British Telecommunications plc
CR CR CR
IR
ER
MH
ER
IR IR
ER
MH
•Subsequent movement...
(0,0,0,3,i)
(0,0,0,4,i)
(0,0,0,5,i)
CR
IR
ER
AR
(0,0,0,5,i)
(0,0,0,6,i)
(0,0,0,6,i)
(0,0,0,7,i)
(0,0,0,8,i)
(-1,0,0,0,i)
(0,0,0,4,i)(0,0,0,4,i) (0,0,0,5,i)
(-1,0,0,4,i)
(-1,0,0,3,i)
(-1,0,0,2,i)
(-1,0,0,1,i)(0,0,0,1,i)
(0,0,0,2,i)
(0,0,0,3,i)
(0,0,0,4,i)
(0,0,0,5,i)AR AR AR(-1,0,0,5,i)
IPCN2000, Paris, France©1997 British Telecommunications plc
CR CR CR
IR
ER
MH
ER
IR IR
ER
MH
... results in similar behavior
(0,0,0,3,i)
(0,0,0,4,i)
(0,0,0,5,i)
CR
IR
ER
(0,0,0,4,i)(0,0,0,4,i) (0,0,0,5,i)
(-2,0,0,5,i)
(-2,0,0,4,i)
(-2,0,0,3,i)
(-2,0,0,2,i)
(-2,0,0,1,i)
(-2,0,0,0,i)
(0,0,0,5,i)
(0,0,0,6,i)
(0,0,0,6,i)
(0,0,0,7,i)
(0,0,0,8,i)(-1,0,0,5,i)
(-1,0,0,3,i)
(-2,0,0,6,i)
(-2,0,0,7,i)(0,0,0,1,i)
(0,0,0,2,i)
(0,0,0,3,i)
(0,0,0,4,i)
(0,0,0,5,i) ARAR AR AR
(-1,0,0,4,i)
IPCN2000, Paris, France©1997 British Telecommunications plc
• When mobile powers off, DAG is erased • Current AR hands address back to home AR • ‘Unicast-Directed Erase Update’ (UDEU)
MH(0,0,0,0,i)
DAG ErasureCR CR CR
IR
ER ER
IR IR
ER
(0,0,0,3,i)
(0,0,0,4,i)
(0,0,0,5,i)
CR
IR
ER
(0,0,0,4,i)(0,0,0,4,i) (0,0,0,5,i)
(-2,0,0,5,i)
(-2,0,0,4,i)
(-2,0,0,3,i)
(-2,0,0,2,i)
(0,0,0,5,i)
(0,0,0,6,i)
(0,0,0,6,i)
(0,0,0,7,i)
(0,0,0,8,i)(-1,0,0,5,i)
(-1,0,0,4,i)
(-1,0,0,3,i)
(-2,0,0,6,i)
(-2,0,0,7,i)(0,0,0,1,i)
(0,0,0,2,i)
(0,0,0,3,i)
(0,0,0,4,i)
(0,0,0,5,i)
UDEU
ARAR AR AR
IPCN2000, Paris, France©1997 British Telecommunications plc
CR CR CR
IR
ER ER
IR IR
ER
MH
(0,0,0,1,i)
(0,0,0,2,i)
(0,0,0,3,i)
(0,0,0,4,i)
(0,0,0,5,i)
(0,0,0,3,i)
(0,0,0,4,i)
(0,0,0,5,i)
CR
IR
ER
(0,0,0,5,i)
(0,0,0,6,i)
(0,0,0,7,i)
(0,0,0,8,i)
(0,0,0,9,i)
(0,0,0,0,i)
•DAG restored to original condition.•Home AR sends Erase Update Ack (EUA)•Current AR completes 3-way handshake (EUA-Ack)
(0,0,0,4,i)(0,0,0,4,i) (0,0,0,5,i)
UDEU
EUA
EUAA
ARAR AR AR
IPCN2000, Paris, France©1997 British Telecommunications plc
Scalable Native-Routed Mobility
CRs
IRs
ERs
ARs
Scaled for 200 hosts per AR- 4CRs, 16IRs, 160ERs, 1600ARs- 320000 mobile hosts in domain
dual-homed topology
• Approx. 2000 Routers and 320000 mobile hosts• Max. Avg. Route Table Size approx. 13200 routes with native IP routing.
Route Table Size
0 5000 10000 15000
Access Router
Edge Router
Inter. Router
Core Router
Rout
er T
ype
Number of Routes
AR (subnet) Routes
Mobile Host Routes
IPCN2000, Paris, France©1997 British Telecommunications plc
Questions?
IPCN2000, Paris, France©1997 British Telecommunications plc
Active Mobile Route Injection
CRs
IRs
ERs
ARs
•Scaled for 200 hosts per AR
single-homed topology
• Number of host routes per router increases towards core
Host Route Injection
0 5000 10000 15000 20000
Access Router
Edge Router
Inter. Router
Core Router
Rout
er T
ype
Host Routes per Router
CR2_ER4_AR16
CR4_ER16_AR144
CR4_ER40_AR400
CR4_IR16_ER160_AR1600
IPCN2000, Paris, France©1997 British Telecommunications plc
Host Route Injection (percentage)
0 10 20 30 40 50
Access Router
Edge Router
Inter. Router
Core Router
Rout
er T
ype
Host Routes per Router as Percentage of Total Hosts
CR2_ER4_AR16
CR4_ER16_AR144
CR4_ER40_AR400
CR4_IR16_ER160_AR1600
Domain Scaling Effects
CRs
IRs
ERs
ARs
single-homed topology
• Number of host routes per router decreases as domain size increases
IPCN2000, Paris, France©1997 British Telecommunications plc
Host Route Injection
0 1 2 3 4 5 6
Access Router
Edge Router
Inter. Router
Core Router
Route
r Typ
e
Host Routes per Router as Percentage of Total Hosts
CR4_IR16_ER160_AR1600
D_CR4_IR16_ER160_AR1600
Effect of Dual-Homed Topology
CRs
IRs
ERs
ARs
dual-homed topology
• Dual-homed: host state disappears from Core Routers • redistributed to more numerous Edge Routers
IPCN2000, Paris, France©1997 British Telecommunications plc
Comparison with HAWAII
CRs
IRs
ERs
ARs
Scaled for 277 mobiles per AR (BS)- 4CRs, 16IRs, 160ERs, 1600ARs
- 442514 active mobiles in domain
dual-homed topology
• Max. Avg. Route Table Size approx. 17600 routes.• cf. HAWAII with 140 ARs (BSs) has 38,720 mobile host routes per domain router
Route Table Size
0 10000 20000 30000 40000 50000
Access Router
Edge Router
Inter. Router
Core Router
Domain Router (HAWAII)
Route
r Type
Number of Routes
AR (subnet) Routes
Mobile Host Routes
(for 140 ARs)
(for 1600 ARs)
Domain Router