1. Shortest Path Bridging IEEE 802.1aq Overview
Insightful Technology Talk
Don Fedyk Janos Farkas Mick Seaman Peter Ashwood-Smith
IEEE Interim San Diego July 14th 2010

2. Acknowledgments Nigel Bragg Guoli Yin Paul Unbehagen David Allan
Authors, Editors and contributors have all have many many years in the industry working in Ethernet, IP, MPLS, ATM, X.25, multiple Standards Bodies

3. Outline Project scope and introduction Requirements SPB mechanisms
SPBV
SPBM
Applications
Examples
References

4. You need someone in Marketing
Outline
Cut down the length
Condense
Project scope and introduction
Requirements
SPB mechanisms
SPBV
SPBM
Applications
Examples
References
Stress the high points
Use an IPAD
Boring
Reference Material
You need someone in Marketing
Too Long
Impress
Stimulate Discussion

5. Ethernet Bridging is successful but
Need a modern control plane address
Arbitrary LANS
SOURCE
ROOT
A1.. A100
DEST
2 - LEARN A1..A100

6. Load Sharing - Visually
All links usable
Animation Courtesy of
Guoli Yin - Huawei

7. But Moore’s law and technology trends are on our side!
SPB Challenges
L2 networks that scale.
Use of arbitrary mesh topologies.
Use of (multiple) shortest paths.
Efficient broadcast/multicast routing and replication points.
Avoid address learning by tandem devices.
Get recovery times into 100’s of millisecond range for larger topologies.
Good scaling without loops.
Allow creation of very many logical L2 topologies (subnets) of arbitrary span.
Maintain all L2 properties within the logical L2 topologies (transparency, ordering, symmetry, congruence, shortest path etc).
Reuse all existing Ethernet OA&M 802.1ag/Y.1731
But Moore’s law and technology trends are on our side!

8. How does it work? From Operators Perspective Internally Use IS-IS !!!
Plug NNI’s together
Group ports/c-vlan/s-vlan at UNIs that you want to bridge (224 groups=‘services’ SPBM mode.)
Assign an I-SID to each group..
Internally Use IS-IS !!!
IS-IS reads box MAC, forms NNI adjacencies
IS-IS advertises box MACs (so no config).
IS-IS reads UNI port services and advertises.
Computations produce FIBs that bridge service members.

9. Pushing Scale in Flat networks
SPBV
SPBM
Metro Core Network
Reliability
Auto-discovery
Load sharing
Managed addresses
Access Network
Bandwidth efficiency
Unknown or managed addresses
Enterprise Network
Plug & Play
Easy to operate
Unknown addresses
MAC learning
in data plane
in control plane
IEEE 802.1aq
VLANS
Data Center
Using the project numbers (one SPBM Domain of 1000 nodes)
Easily address Millions of devices
Why? Orthogonal Address, Service and Topology

10. Orthogonal Topology Common Spanning Tree (CST)
Internal Spanning Tree (IST)
Common and Internal Spanning Tree
SPT Region
IST
SPT Region
MST Region
IST
MST Region
CST
RSTP bridges

11. Orthogonal Service and Address
Provider
Backbone
Bridges
802.1ah
Encapsulation for virtualization is important in many networks
Provider
Bridges
802.1ad
Ethernet
Ethertype
VLAN
C-VID
Ethernet
802.3
C-TAG
S-VID
S-TAG SA
Ethertype DA
C-VID
I-SID
Ethertype
C-TAG
I-TAG
C-VID
S-VID
B-VID
Ethertype
Q-TAG
S-TAG
B-TAG
Consistent
Forwarding SA SA SA
B-SA DA DA DA
B-DA
1998
2005
2008
Standard Approved
It is a very good Data Plane!

12. SPBM Multicast Addresses The SPBM Trifecta
By constructing local IEEE Multicast Addresses the Control Plane has complete flexibility to build multicast trees.
Computation, Source Identification, Service Identification

13. Congruency Same Forward and Reverse Shortest Path
Shortest path between any two points is both the same and symmetrical for unicast and multicast D E C H A J G
Bridge “A” B I F
Same Forward and Reverse Shortest Path
Learning SPBV, OAM, Frame Ordering

14. Green and Blue Costs are equal A-C-D and A-B-D
Equal Cost Trees
Green and Blue Costs are equal A-C-D and A-B-D D E C H A J G
Bridge “A” B I F
Optional Multipath Load Balancing different services

15. Multicast Forwarding for I-SID 5
SPBM Multicast Groups
I-SID 5
Multicast Forwarding for I-SID 5
IS-IS
I-SID 5
IS-IS D E
IS-IS
IS-IS C H
IS-IS
IS-IS
IS-IS A
IS-IS J G
Bridge “A” B
I-SID 5
IS-IS
IS-IS
No Multicast Forwarding for I-SID 5 (Shortest path to E but not part of the tree) I F
I-SID 5
I-SIDs define efficient subsets

16. Multicast Forwarding for I-SID 45
SPBM Multicast P2MP
Multicast Forwarding for I-SID 45
IS-IS
I-SID 45
Leaf
IS-IS D E
IS-IS
IS-IS
I-SID 45
Leaf C H
IS-IS
IS-IS
IS-IS A
IS-IS J G
Bridge “A” B
I-SID 45
Root
IS-IS
IS-IS I F
I-SID 45
Leaf
E-TREE I-SIDs Root to/From Leaf only

17. SPBM Per I-SID Controls
Aggregation
Replication
SPT Number
Customer - Group
Head Node
Each I-SID is a VLAN

18. Implementation of Congruency
Tie-breaking extension to Dijkstra for the case of equal cost multiple paths
Sorted List of transit node IDs comprising a path are unique/deterministic. Ranking them produce deterministic default winner.
{2,6} < {3,7} < {4,7}
Same algorithm is used both for unicast and multicast
Bridge3 1 1
Bridge7 1 1
Bridge1
Bridge4 1
Bridge5 1
Bridge2 1 1
Bridge6

19. Load sharing
16 trees are created by applying the previous algorithm AFTER XORing BridgeID’s with 16 different bit-masks.
Example XORing with 0xff…ff (invert) selects largest ranked path so {~7,~4} wins..
Each mask is assigned to a B-VID (SPBM mode)
MASKS | B-VID 0x00 0x11 0x22 0x33 0x44 0x55 0x66 0x77 0x88 0x99 0xAA 0xBB 0xCC 0xDD 0xEE 0xFF
Low
Bridge3 1 1
Bridge7 1 1
Bridge1
Bridge4 1
Bridge5 1
Bridge2 1 1
Bridge6
High

20. Load Sharing - Visually
All links usable
Animation Courtesy of
Guoli Yin - Huawei

21. ANIMATION FOR E-LAN ‘100’ WITH 7 MEMBERS
Highlighted is the routing from each member to all others.
Note the symmetry.
Unicast and multicast
Follows exactly these
Routes.
Multicast can be replicated at fork points or head end replicated to the uni-cast paths by configuration at edge.
Animation Courtesy of
Guoli Yin - Huawei

22. Loop Prevention Loop Prevention (Not new) Loop Mitigation (New)
Policy : Loop Free by never allowing a loop to form
“Never forward a Frame unless the neighbor node has agreed to accept it”
Mechanism: Don’t populate an FDB entry until you synchronize with next-hop neighbor.
Loop Mitigation (New)
Policy: Discard potential looping frames
“Never accept a Frame from a neighbor node that you do not expect”
Mechanism: Ingress check. Source DA/VID must be expected. Local Policy.
Loop Prevention is sufficient, but Loop Mitigation is faster during changes
Loop Prevention for Multicast and Loop Mitigation for Multicast and Unicast

23. Application Data Center
Totally compatible with Vmware server functions:
OA&M, motion, backup etc.
Apps that sit on Vmware ‘just work’.
Totally compatible with Microsoft load balancing (multicast over the L2)
VRRP transparent.
It just makes the L2 part of the DC larger and better utilized.
Compatible with emerging Inter DC overlay work.

24. Application Data Center
Multiple shortest path routing (inter server traffic)
Deterministic traffic flows.
Flexible subnet – expand/shrink anywhere.
Virtualization operates in subnet.
Fully compatible with all Data Center Bridging protocols & OA&M.
Address isolation through m-in-m
Fast recovery
No loops * *
AA22
AA24
AA25
AA26
BB39
BB40
BB41
BB42
CC25
CC26
CC27
CC28
DD77
DD78
DD79
DD80

25. 802.1aq ISIS LSP extensions at a glance
LSPID Seq Num Checksum ….
x a 0xc01f …..
SOURCE
HOST NAME Instance_1
NLPID SPB (0xC1)
AREA ADDR
NBR ID COST: 10
NBR ID COST: 10
SPSOURCEID
SPB ECT-ALGORITHM 1 ECT-VID 101
SPB ECT-ALGORITHM 0 ECT-VID 100
SPB BMAC
ECT-VID
SPB ISID T&R
ECT-VID
SPB ISID T&R
(1) :4 10
(2)
255
(3) :1 :3 10
256
(4)
LSP fragment for node :1 with 2 peers :4 and :3 and two services 255, 256
(5)

26. EXAMPLE NETWORK : Full Transit Replication 36 node network
255
255
255
255
255
255
255
Full Transit Replication
255
36 node network
8 member E-LAN ISID=255

27. EXAMPLE – ISIS PEERS AT NODE :3
<ottawa >d spb
The current global spb information is :
Device HMAC is
Spsid is
Ect vlan amount is 2
Ect vlan sequence number [1] is: vlan 100 !
Ect vlan sequence number [2] is: vlan 101 !
<ottawa >
<ottawa >d isis peer
Peer information for ISIS(1)
System Id Interface Circuit Id State HoldTime Type
Vlanif Up 26s L1
Vlanif Up 23s L1
Vlanif Up 27s L1
Vlanif Up 27s L1
Vlanif Up 25s L1
Total Peer(s): 5
Logging on to node :3 We can see the basic SPB info and the ISIS peers….

28. EXAMPLE – LSDB at node :3 Database information for ISIS(1)
Level-1 Link State Database
LSPID Seq Num Checksum Holdtime Length ATT/P/OL
x00000fd2 0x1cea /0/0
* 0x x3d /0/0
x00000ff8 0xd1d /0/0
x00000b3b 0x9ba /0/0
x00000b3b 0xbc /0/0
x00000b3b 0xce /0/0
x00000b3e 0xebe /0/0
x00000b3b 0x8b /0/0
a x00000b3b 0x57a /0/0
b x00000b3a 0x /0/0
c x00000b3a 0x /0/0
d x00000b3a 0x89fd /0/0
e x00000b39 0x /0/0
f x00000b3a 0xdabe /0/0
x00000b3b 0x810e /0/0
x00000b3a 0x1b /0/0
x00000b39 0x1b3e /0/0
x00000b3a 0x943a /0/0
x00000b3b 0xdff /0/0
x00000b41 0xdade /0/0
x00000b3e 0xa /0/0
x00000b40 0x /0/0
x00000b3a 0xadee /0/0
x00000b3a 0xcff /0/0
a x00000b3b 0xb /0/0
b x00000b3b 0x /0/0
c x00000b3b 0x /0/0
d x00000b3b 0xa /0/0
e x00000b3a 0xf5c /0/0
f x00000b3b 0x8a /0/0
x00000b3a 0x960a /0/0
x00000b3b 0x5b /0/0
x00000b3a 0x /0/0
x00000b3b 0x /0/0
x00000b39 0xc8ec /0/0
*(In TLV)-Leaking Route, *(By LSPID)-Self LSP, +-Self LSP(Extended),
ATT-Attached, P-Partition, OL-Overload

29. EXAMPLE LSP VERBOSE OF NODE :1 at NODE :3
<ottawa >d isis lsdb verbose
Database information for ISIS(1)
Level-1 Link State Database
LSPID Seq Num Checksum Holdtime
x00000fd3 0x1aeb
SOURCE
NLPID SPB(0xC1)
AREA ADDR
+NBR ID COST: 10
+NBR ID COST: 10
SPB ECT-ALGORITHM 0 ECT-VID 100
SPB ECT-ALGORITHM 1 ECT-VID 101
SPB ECT-ALGORITHM 2 ECT-VID 0
…….
SPB ECT-ALGORITHM 15 ECT-VID 0
SPSID
SPB BMAC
ECT-VID
SPB ISID T&R
<ottawa >

30. EXAMPLE – NODE :3 ROUTE TO :10 (first equal cost path)
<ottawa >d spb umac
BMAC BVLAN IF NAME
GE2/0/11
GE2/0/11
GE2/0/12
GE2/0/12
GE2/0/16
GE2/0/16
GE2/0/16
GE2/0/17
GE2/0/17
GE2/0/17
GE2/0/17
GE2/0/17
GE2/0/12
GE2/0/18
a GE2/0/17
a GE2/0/18
b GE2/0/18
b GE2/0/18
c GE2/0/18
c GE2/0/18
d GE2/0/16
d GE2/0/18
e GE2/0/16
e GE2/0/18
f GE2/0/16
f GE2/0/18
GE2/0/16
GE2/0/18
...
GE2/0/12
GE2/0/18
Total unicast fib entries is 68
<ottawa >

31. EXAMPLE – NODE :3 ROUTE TO :10 (second equal cost path)
<ottawa >d spb umac
BMAC BVLAN IF NAME
GE2/0/11
GE2/0/11
GE2/0/12
GE2/0/12
GE2/0/16
GE2/0/16
GE2/0/16
GE2/0/17
GE2/0/17
GE2/0/17
GE2/0/17
GE2/0/17
GE2/0/12
GE2/0/18
a GE2/0/17
a GE2/0/18
b GE2/0/18
b GE2/0/18
c GE2/0/18
c GE2/0/18
d GE2/0/16
d GE2/0/18
e GE2/0/16
e GE2/0/18
f GE2/0/16
f GE2/0/18
GE2/0/16
GE2/0/18
...
GE2/0/12
GE2/0/18
Total unicast fib entries is 68
<ottawa >

32. EXAMPLE: E-LAN MCAST ROUTES FROM :1 (left) and :26 (right)
SRC
SRC
Here are the multicast routes from node 1 for service 255 and also from node 26 for service 255. Note the symmetry in the route between the two multicast trees. The unicast route between :1 and :26 is also along that same path for the chosen B-VID. Since we’ve asked for transit replication for all members of the E-LAN we install MCAST …

33. EXAMPLE: E-LAN MCAST ROUTES FROM :1 (left) and :26 (right)5
| FLG | IN/IF | DESTINATION ADDR | BVID | OUT/IF(s)
| | if/01 | ff | 0100 | {if/5,if/6 } …. 6 1 10 16 11
SRC
<ottawa >d spb mmac
IN_PORT VID BMAC OUT_PORT
...
GE2/0/ ff GE2/0/16, GE2/0/10
Total multicast num is 7
<ottawa >
MULTICAST ADDRESS IS: [ SOURCE = | ISID=00-00-ff ]
We only get this state if we configure transmit membership in the E-LAN.
Transmit still possible without multicast state but uses serial replication at head end.
Operator chooses trade-off between state/bandwidth usage.

34. Here are all mFIBs on nodes :3 and :13 related to this E-LAN.
| FLG | IN/IF | DESTINATION ADDR | BVID | OUT/IF(s)
| | if/01 | ff | 0100 | {if/5,if/6 }
| | if/01 | ff | 0100 | {if/5,if/6 }
| | if/01 | a00-00ff | 0100 | {if/5,if/6 }
| | if/05 | d00-00ff | 0100 | {if/1,if/3,if/6 }
| | if/06 | e00-00ff | 0100 | {if/1,if/3,if/5 }
| | if/03 | ff | 0100 | {if/5,if/6 }
Here are all mFIBs on nodes :3 and :13 related to this E-LAN.
<ottawa >d spb mmac
IN_PORT VID BMAC OUT_PORT
GE2/0/ ff GE2/0/10, GE2/0/11
GE2/0/ ff GE2/0/10, GE2/0/11
GE2/0/ a00-00ff GE2/0/10, GE2/0/11
GE2/0/ d00-00ff GE2/0/10, GE2/0/11
GE2/0/ e00-00ff GE2/0/10, GE2/0/11
GE2/0/ ff GE2/0/16, GE2/0/10
GE2/0/ ff GE2/0/16, GE2/0/11
Total multicast num is 7
<ottawa >

35. References
“IEEE 802.1aq”
“IS-IS Extensions Supporting IEEE 802.1aq Shortest Path Bridging”
“IEEE 802.1aq” :
“Shortest Path Bridging – Efficient Control of Larger Ethernet Networks” : upcoming IEEE Communications Magazine – Oct 2010
“Provider Link State Bridging” : IEEE Communications Magazine V46/N9– Sept ieeecommunicationsmagazinevol46no9sep2008-carrierscaleethernet.pdf
“Shortest Path Bridging IEEE 802.1aq” NANOG49 – June

36. Glossary B-MAC Backbone MAC BEB Backbone Edge Bridge
BCB Backbone Core Bridge
C-VID Customer VID
CFM Connectivity Fault Management
CST Common Spanning Tree
ELINE Ethernet Point to Point Service
ELAN Ethernet LAN Service
ETREE Ethernet Hub and Spoke Service
FDB Filtering Data Base
FID Forwarding Identifier
I-SID (802.1ah) Service Identifier
IGP Interior Gateway Protocol (Typically link state)
IS-IS Intermediate System to Intermediate System (IGP)
IST Internal Spanning Tree
LAG Link Aggregation
LAN Local Area Network
MAC Media Access Control
MACinMAC see PBB
MEP Maintenance End point
MIP Maintenance Intermediate point
MMAC Multicast MAC
MSTP Multiple Spanning tree protocol
MMRP Multiple MAC Registration Protocol
OAM Operations, Administration and Maintenance
PB Provider Bridges IEEE 802.1ad
PBB Provider Backbone Bridging IEEE 802.1ah
PBB-TE PBB Traffic Engineering IEEE 802.1Qay
QinQ see PB
S-VID Service VID
SPB Shortest Path Bridging IEEE 802.1aq
SPBM Shortest Path Bridging MAC
SPBV Shortest Path Bridging VID
SPT Shortest Path Tree
STP Spanning tree protocol
RSTP Rapid Spanning tree protocol
TTL Time To Live
VID VLAN Identifier
VLAN Virtual LAN

37. Thank You