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PBB-TE Requirements

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

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PBB-TE Requirements

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

  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 PBB-TE ≥ 2000 PBB < 2000

  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.

  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.

  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.

  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

  7. Additional benefit of using EtherType to differentiate PBB-TE traffic and PBB traff:

  8. Provisioning Error at Switch H E 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 Red transport not provisioned (by error) 1 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.

  9. E 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 Red transport not provisioned (by error) 1 BVID10 correctly provisioned for transport BVID10 incorrectly provisioned for bridging Impact of PBT Configuration Error • 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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