1. bsultan@huawei.com ldunbar@huawei.com
22.January 2007
PBB-TE Requirements

2. Problem: Simple partition of BVID space
Non-sequential PBB BVID assignments
BVID assignments for simply partitioned PBB/PBB-TE
Assume:
BVIDs not assigned sequentially for PBB
PBB-TE allows only simple partition of BVID space
BVID < N  PBB
BVID ≥ N  PBB-TE
Observe:
Migration requires reassignment of many PBB BVIDs
BVID
TYPE
4095 -
4094
2020
PBB
2019
2018
2017
2016 5 4 3 2 1
BVID
TYPE
4095 -
4094
2020
2019 TE
2018
2017
2016 5
PBB 4 3 2 1
PBB-TE ≥ 2000
PBB < 2000
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3. Remedy: Distinct assignment per BVID
Non-sequential PBB BVID assignments
‘Non-disruptively’ adding PBB-TE BVID assignments
Conclusions:
Simple partition of BVID space is insufficient
Individual assignment of BVIDs is needed
Statement of requirement:
The introduction of TE in a PBBN should not require reassignment of BVID values currently used for PBB traffic.
It is an option to allow a simple partition of the space when PBB reassignment is not a concern.
BVID
TYPE
4095 -
4094
2020
PBB
2019
2018
2017
2016 5 4 3 2 1
BVID
TYPE
4095 -
4094
2020
PBB
2019
2018
2017 TE
2016 5 4 3 2 1
Page 3

4. Option to eliminate need to partition BVID space
PBB BVID assignments
PBB-TE BVID assignments
Distinguish PBB vs. PBB-TE traffic by Ethertype
or other convenient marking.
guarantee that PBB forwarding cannot interfere with PBB-TE forwarding
greatly simplifies PBB / PBB-TE BVID assignment
Understood that BCB (PB) need additional function to interpret both Ethertypes.
Considering that PBB-TE requires all BCB(PB) nodes to change forwarding behavior anyway, it is not too much additional function.
BVID
TYPE
4095 -
4094
2020
PBB
2019
2018
2017
2016 5 4 3 2 1
BVID
TYPE
4095 -
4094
2020
2019
2018
2017 TE
2016 5 4 3 2 1
Page 4

5. Problem: PBB traffic interferes with PBB-TE traffic
PBB-TE is provisioned along path and policed at ingress edge (no problem)
PBB paths are not provisioned
Difficult to know appropriate rate for edge policing
Must give PBB-TE traffic absolute priority over PBB traffic
Not possible if PBB already using highest priority value
Distinct PRI spaces provides natural solution
PBB and PBB-TE can each use full set of priority values
PBB-TE always granted absolute priority over PBB
PBB-TE (red) traffic granted absolute priority over PBB (blue) traffic.
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6. Requirements
Base is to allow any BVID to be assigned PBB or PBB-TE
Option is to allow a partition between PBB and PBB-TE BVIDs.
Option for differential treatment (e.g., by Ethertype) of PBB and PBB-TE
Avoid BVID and/or PRI reassignment on migration
Ethertype is reasonable way to provide this option
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7. Additional benefit of using EtherType to differentiate PBB-TE traffic and PBB traff:
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8. Provisioning Error at Switch H
Backbone Edge Bridge (BEB) IEEE 802.1ah B 4
Backbone Core Bridge (BEB) IEEE 802.1ad A F G
Backbone Spanning Tree
Red transport traffic (on backbone VID 10) 3
Blue transport traffic (on backbone VID 10) 2 H I 1
Red transport not provisioned (by error)
BVID10 correctly provisioned for transport
BVID10 incorrectly provisioned for bridging
Switch H has been incorrectly provisioned so that
backbone VLAN ID (BVID) 10 is associated with bridging instead of transport
provisioning of the red transport has been omitted.
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9. Impact of PBT Configuration Error
Backbone Spanning Tree
Red transport traffic (on backbone VID 10)
Blue transport traffic (on backbone VID 10)
Backbone Edge Bridge (BEB) IEEE 802.1ah
Backbone Core Bridge (BEB) IEEE 802.1ad
Red transport not provisioned (by error) A B E F G H I 1 2 3 4
BVID10 correctly provisioned for transport
BVID10 incorrectly provisioned for bridging
Frame enters the red transport at I.
Frame correctly forwarded from I to H via red transport.
Frame flooded from H to B and from H to F via Spanning Tree due to provisioning errors at H.
Frame is erroneously forwarded from B to A via blue transport.
Consequence is that capacity on link B-A, committed to the blue transport, is consumed by the red transport. The red transport is denied the level of service for which it has contracted.
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