Shortest Path Bridging IEEE 802.1aq Tutorial and Demo

Shortest Pat
IEEE 80

Tutorial an

NANOG 50

Peter Ashwo

Fello

peter.ashwoodsmi

th Bridging
02.1aq
nd Demo

0 Oct 2010

ood-Smith

ow

[email protected]

Abst

802.1aq Shortest Path Bridging is b
evolution of the various spanning tr
shortest path routing, multiple equa
topologies, faster convergence, vas
single point provisioning for logical
etc), abstraction of attached device
devices, head end and/or transit m
the full suit of 802.1 OA&M.

Applications consist of STP replace
L2 Internet Distributed Exchange p
sized Metro Ethernet control planes

tract

being standardized by the IEEE as an
ree protocols. 802.1aq allows for true
al cost paths, much larger layer 2
stly improved use of the mesh topology,
membership (E-LINE/E-LAN/E-TREE
e MAC addresses from the transit
multicast replication , all while supporting

ement, Data Center L2 fabric control,
point fabric control, small to medium
s. L2 wireless network backhaul….

2

Out

•  Challenges
•  What is 802.1aq/SPB
•  Applications
•  How does it work
•  Example with hopefu

lab (assuming conne

tline

B

ully live demo from my
ectivity available)

3

Challe

•  L2 networks that scale to ~10
•  Use of arbitrary mesh topolog
•  Use of (multiple) shortest pat
•  Efficient broadcast/multicast r
•  Avoid address learning by tan
•  Get recovery times into 100’s

topologies.
•  Good scaling without loops.
•  Allow creation of very many lo

of arbitrary span.
•  Maintain all L2 properties with

(transparency, ordering, symm
path etc).
•  Reuse all existing Ethernet O

enges

000 bridges.
gies.
ths.
routing and replication points.
ndem devices.
s of millisecond range for larger

ogical L2 topologies (subnets)

hin the logical L2 topologies
metry, congruence, shortest

OA&M 802.1ag/Y.1731

4

Example ST

2- poor
routes

ROOT

TP 36 nodes

1- Can’t use
these links

Source
A1.. A100

Dest

3 – Must learn A1..A100

5

Out

•  Challenges
•  What is 802.1aq/SP
•  Applications
•  How does it work
•  Short Demo (remote

tline

PB
e switches if possible)

6

What is 802

•  IEEE protocol builds o
•  A new control plane fo

–  Leverage existing inexpe
–  Q-in-Q mode called SPBV
–  M-in-M mode called SPB

•  Backward compatible

–  802.1ag, Y.1731, Data C

•  Multiple loop free shor

–  Excellent use of mesh co
–  Currently 16, path to 100

hop.

•  Optimum multicast

–  head end or tandem repli

2.1aq/SPB 7

on 802.1 standards
or Q-in-Q and M-in-M

ensive ASICs
V
BM

to 802.1

Center Bridging suite

rtest paths routing

onnectivity
00’s including hashed per

ication

What is 802.1a

•  Light weight form of tr

–  Head end assignment of
–  Deterministic routing - of

•  Scales to ~1000 or so

–  Uses IS-IS already prove
–  Huge improvement over

•  Good convergence wi

–  sub second (modern pro
–  below 100ms (use of har
–  Includes multicast flow w

Pre-standard seeing 300

•  IS-IS

–  Operate as independent
IP, supports Multi Topolo
efficiently.

aq/SPB (cont’d)

raffic engineering

f traffic to 16 shortest paths.
ffline tools predict exact routes.

devices

en well beyond 1000.
the STP scales.

ith minimal fuss

ocessor, well designed)
rdware multicast for updates)
when replication point dies.
0ms recovery @ ~50 nodes.

IS-IS instance, or within IS-IS/
ogy to allow multiple instances

8

What is 802.1a

•  Membership advertise
topology.

–  Minimizes complexity, ne
–  Support E-LINE/E-LAN/E
–  All just variations on mem

•  Address learning restr

–  FDB is computed and po
–  Unicast and Multicast han
–  Nodal or Card/Port addre

•  Computations guarant

–  Symmetry (same in both
–  Congruence (unicast/mul
–  Tune-ability (currently 16

allows more)

aq/SPB (cont’d)

ed in same protocol as

ear plug-and-play
E-TREE
mbership attributes.

ricted to edge (M-in-M)

opulated just like a router.
ndled at same time.
essing for dual homing.

tee ucast/mcast…

directions)
lticast follow same route)
6 equal costs paths – opaque

9

End result

Multiple Shortest Path ro

t - Visually

All links usable

outing + Ethernet OA&M 10

SPF trees form m

Shortest Path First Tree becomes tem
automatically to proper membership.

multicast template

mplate for multicast tree and is pruned

11

Edge Learnin

Dst.B-MAC
Src.B-MAC
B-VLAN
801.1AH/ I-SID
Dst.C-MAC
Src.C-MAC
C-VLAN
Payload

A|B?

:A
Learn B via 20!

ng - Visually

:B
Learn A via 1!

Learning restricted to edges
and only where I-SID tree
reaches. Mac-in-Mac encap. 12

Out

•  Challenges
•  What is 802.1aq/SPB
•  Applications
•  How does it work
•  Short Demo (remote

tline

B
e switches if possible)

13

Application (M|R)S

Small # of R

trees

Unused
links

Regions R

for scale

•  Many more nodes w
•  Low effort to get goo
•  Fast convergence –
•  Address isolation m

STP replacement

Large number All links
of source specific usable
trees (computed).
No regions
needed

Scoped exactly
to C-VLAN or
S-VLAN members

without regions
od routing
– link state v.s. distance vec
m-in-m.

14

Data Center -

BIG L2

trends

Treat DC network as
one big L2 switch by
combining 100’s of smaller
switches in ‘non blocking’
topology – why?

•  Any server anywhere.

•  Any router anywhere.

•  Any appliance anywhere.

•  Any VM anywhere.
- Any IP address anywhere.
- Any subnet anywhere.

•  Any storage anywhere.

•  Minimal congestion issues.

•  Total flexibility for power use

15

Application D

•  Multiple shortest path routing
•  inter server traffic

•  Deterministic traffic flows.

•  Flexible subnet – expand/shrink
•  Virtualization operates in sub

•  Fully compatible with all 802.1
Data Center Bridging protocols &

•  Address isolation through m-in-m

•  Fast recovery

•  No loops

Data Center

anywhere.
bnet.

& OA&M. 1.1.1.*
m 1.1.2.*

16

Application Data Center VM ‘hot

Ethernet Bus ( 802.1aq logical network for I-SID1/ VM
Ethernet Bus ( 802.1aqL logical network for I-SID2 /VM

Dst.B-MAC
Src.B-MAC
B-VLAN
801.1AQ/ I-
SID
Dst.C-MAC
Src.C-MAC
C-VLAN
Payload

Dst.C-
MAC
Src.C-
MAC
C-VLAN
Payload

NMS

t’ migration (no interruption)

MG1 )

MG2 )

Dst.B-MAC
Src.B-MAC
B-VLAN
801.1AQ/ I-
SID
Dst.C-MAC
Src.C-MAC
C-VLAN
Payload

Dst.C-
MAC
Src.C-
MAC
C-VLAN
Payload

17

Application Data

•  Totally compatible with Vmw
•  OA&M, motion, backup e
•  Apps that sit on Vmware

•  Totally compatible with Micro
over the L2)

•  VRRP transparent (primary/s
or proprietary variations on s

•  It just makes the L2 part of t
utilized.

•  Compatible with emerging In

a Center (cont’d)

ware server functions:
etc.
e ‘just work’.

osoft load balancing (multicast

stdby rtr per subnet)
same protocol.

the DC larger and better

nter DC overlay work.

18

Application High Performance switchi

Good A1 A2

numbers 16 x 32 x 100
“16” using 48 x 2
So 1
& “2”
levels.

B1 B2 B3 B4 5120
S1,1 S1,160 S3,1 S3,160

•  48 switch non blocking 2 layer L2 fabric 100
•  16 at “upper” layer A1..A16 fab
•  32 at “lower” layer B1.. B32
•  16 uplinks per Bn, & 160 UNI links per Bn
•  32 downlinks per An

ing cluster – assume 100GE NNI links
A15 A16

32 x 100GE

0GE = 51.2T

2T switches
102T

16 x 100GE

B29 B30 B31 B32160 x 10GE

x 10GE

S32,1 S32,160

•  (16 x 100GE per Bn )x32 = 512x100GE = 51.2T
•  160 x 10GE server links (UNI) per Bn
•  (32 x 160)/2 = 2560 servers @ 2x10GE per

0+ Terra non blocking interconnection 19
bric (if switches non blocking)

Application Me

•  Very light weight L2VPNs
E-LAN, E-LINE, E-TREE f

•  Can do VPLS style head e
•  Can do p2mp style transit
•  Can support receive only

UNI NNI

etro/L2VPN

s (2^24 data path) of:
flavors (a very cheap VPLS)
end replication
t replication (just one tx flag).
membership (E-TREE)

UNI - E-LINE
= 2 tx/rx members

- E-LAN
> 2 tx/rx members

- E-TREE n rx members
1 tx member.

20

L2 Internet Exc

802.1aq distributed fabric

Service Provider
B

Service
Provider

C

Service Provider
A

Service Provider
B

change Point

Service Provider
B

Service Provider
A

Service Provider
A

Service 21
Provider

C

Out

•  Challenges
•  What is 802.1aq/SPB
•  Applications
•  How does it work

tline

B

22

How does

•  From Operators Perspec
-  Plug NNI’s together
-  Group ports/c-vlan/s-vl
want to bridge (224 gro
mode.)
-  Assign an I-SID to eac

•  Internally
-  IS-IS reads box MAC,
-  IS-IS advertises box M
-  IS-IS reads UNI port se
-  Computations produce
members.

s it work?

ctive

lan at UNIs that you
oups=‘services’ m-in-m

ch group..

forms NNI adjacencies
MACs (so no config).

ervices and advertises.
e FIBs that bridge service

23

Data Path (M

•  C-vlan/S-vlan or untagg
•  Its encapsulated with B
•  Its encapsulated with I-
•  Its encapsulated with B
•  C-DA is looked up, if fo
•  C-DA not found, B-DA i

•  Multicast to all othe
group from ‘me’. O
over unicast.

•  C addresses to B a
learned at UNI only

M-in-M mode)

ged traffic arrives at UNI
B-SA of bridge
-SID configured for group
B-VID chosen for route
ound B-DA is set
is multicast that says:
er members of this I-SID
Or can head-end replicate

address association
y.

24

FDB (unicast M

•  A unique shortest pat
is computed.

•  BMAC of other nodes
to appropriate out int

•  Above is repeated fo
causes a different B-V

•  Symmetry is assured
breaking logic. 16+ d
algorithms permit 16+

M-in-M mode)

th from node to all others

s installed in FIB pointing
terface.

or 16+ shortest paths each
VID to be used.

d through special tie-
different tie-breaking
+ different shortest paths.

25