Transcript new-ashwood-ecmp-alg-0111-v01.ppt

IEEE 802.1aq
control of the
Mac-in-Mac Hash/TTL
B-VID(s)
Jan 2011
Peter Ashwood-Smith
[email protected]
Background
• 802.1aq creates new behavior for a B-VID.
• Traffic on a B-VID within an 802.1aq domain
travels shortest path towards its B-DA, very
different than normal PBB use.
– No learning/Output by computation
– Ingress Check/Discard if incorrect
• Therefore 802.1aq has mechanisms to ensure
B-VID function is agreed to within the 802.1aq
domain.
• To change the function, add or delete a new BVID 802.1aq has mechanisms to advertise and
verify consistency.
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Background
• The function of a B-VID is defined with a tuple:
{ < B-VID > , <ECT-ALGORITHM> }
• The <ECT-ALGORITHM> is further broken down
into a world wide unique OUI and local ‘index’.
• 802.1aq currently defines 17 values all with the
802.1 OUI. These are indexes 0..16.
• Index 0 is for a shared tree (CIST) while indexes
1..17 are for SPF trees with different tie
breakers.
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Tuples are exchanged and verified
:2
:3
:1
:4
:6
:5
B-VID,ECT-ALGORITHM tuples
Are exchanged in hellos and checked
for consistency.
B-VID,ECT-ALGORITHM tuples
are also advertised in LSPs.
Inconsistency is only permitted if a tuple is not in use.
We can therefore introduce a new B-VID, ECT-ALGORITHM and temporary
inconsistency is allowed until we start using it.
We can therefore remove all services from a B-VID, ECT-ALGORITHM and
then start to delete it and inconsistency is allowed while I delete it.
Migration to a new B-VID, ECT-ALGORITHM or away from one then only
requires edge by edge re-provisioning, can be done over days/weeks.
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Algorithm to B-VID association in Hello
+-+-+-+-+-+-+-+-+
|Type= SPB-B-VID| = 5
+-+-+-+-+-+-+-+-+
|
Length
|
(1 byte)
+-+-+-+-+-+-+-+-+-------------------------------+
|
ECT - VID Tuple (1) (6 bytes)
|
+-----------------------------------------------+
|
.........................
|
+-----------------------------------------------+
|
ECT - VID Tuples (N) (6 bytes)
|
+-----------------------------------------------+
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
ECT - Algorithm (32 bits)
|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Base VID (12 bits)
|U|M|RES|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
5
Algorithm to B-VID association in LSP.
+-+-+-+-+-+-+-+-+
|Type = SPB-Inst| = 1
+-+-+-+-+-+-+-+-+
|
Length
|
(1 byte)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
CIST Root Identifier (4 bytes)
|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
CIST Root Identifier (cont) (4 bytes)
|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
CIST External ROOT Path Cost
(4 bytes)
|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
Bridge Priority
|
(2 bytes)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|R R R R R R R R R R R|V|
SPSOURCEID
|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Num of Trees |
(1 bytes)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
VLAN-ID (1) Tuples
(8 bytes)
|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
VLAN-ID (N) Tuples
(8 bytes)
|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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TLV – SPB-Service Instance
+-+-+-+-+-+-+-+-+
|Type = SPBM-SI | = 3
+-+-+-+-+-+-+-+-+
|
Length
|
(1 byte)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
B-MAC ADDRESS
|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
B-MAC ADDRESS (6 bytes)
| Res. |
Base-VID (12 bits) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|T|R| Reserved |
ISID #1
|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|T|R| Reserved |
ISID #2
|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|T|R| Reserved |
ISID #n
|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
A service is assigned to an ALGORITHM indirectly through association
with a Base-VID. The Base-VID of course is part of an ALGORITH,VID
tuple.
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Suggested approach for ECMP
• Assuming an 802.1aq network running
some number of ECT-ALGORITHMS.
• A new B-VID, ECT-ALGORITHM tuple is
assigned and advertised normally.
• The new B-VID, ECT-ALGORITHM would
cause hash based forwarding/TTL
decrement for UNICAST traffic only.
• Migration to/from this B-VID would be
identical to any other B-VID running an AQ
forwarding plane.
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Possible ECMP encodings
ECT-ALGORITHM
UCAST BEHAVIOR
MCAST BEHAVIOR
00-80-C2-00
CIST
CIST
00-80-C2-01
SPF low path id
SPF low path id
00-80-C2-02
SPF low mask 0xFF
SPF low mask 0xFF
….
…
…
00-80-C2-10
SPF low mask 0xEE
SPF low mask 0xEE
00-80-C2-11
ECMP hash alg#1
SPF low path id
00-80-C2-12
ECMP hash alg#1
SPF low mask 0xFF
…
…
…
00-80-C2-20
ECMP hash alg#1
SPF low mask 0xEE
00-80-C2-21
ECMP hash alg#2
SPF low path id
00-80-C2-22
ECMP hash alg#2
SPF low mask 0xFF
…
…
…
00-80-C2-30
ECMP hash alg#2
SPF low mask 0xEE
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