All-Path Bridging Update

IEEE Plenary meeting San Francisco 17-21 July

Jun Tanaka (Fujitsu Labs. Ld.)

Guillermo Ibanez (UAH)

Vinod Kumar (Tejas Networks)

All-Path : Basic Idea

• Modified learning, filtering and forwarding• Addressed to small and medium size networks• Objectives: overcome RSTP limitations and obtain good

latency paths without configuration

MAC=aMAC=b

x

x

Flooding

Blocking

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Scope of All-Path

Scalability

Manageability

SPB, ECMPTRILL

ALL-PATH

Enterprise, Campus, Small datacenter etc.

Simple Less operation Natural load balance

Large area, provider networkLarge datacenter etc.

Both support, loop free, shortest path

LAN

MAN/WAN

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Issue1. Path Recovery

• Mechanism: When unknown unicast frame arriving at bridge with failed link, path fail message is generated per MAC entry towards source bridge, that generates corresponding ARP to re-establish tree.

• Question: If 10K MAC entries are existed in FDB, 10K path fail frames should be generated, is it feasible processing for local CPU, especially in high-speed link (ex. 10GE)?

• It can be applicable for small or medium networks if we are targeting the enterprise, campus and small datacenter etc.

• Moreover, a solution is proposed that minimize the frame generation.

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Path recovery (cont’d)

MAC=aMAC=b

bb bba a a a

a

a

flush “b”flush “b”

flush “b

”

SW1 SW2

SW3

SW4

SW5

SW6

1

2

3

2 2 2 2

2

1 1

1

1

1

3

flush message is terminated because “b” is not binded to port1

May includes two or more…ex. 100s of MAC addresses to be flushed as a list.

Delete entry “b” from FDB and re-sends the flush message to SW1.

When link failure is detected, MAC flush lists (187 MAC / 1500B frame) are flooded. 54 frames by a day for 10K MAC entry.

Avoid unnecessary flooding, MAC list is deleted to shorten.

Issues: How to prevent flush frame loss.

May require CPU processing power.

Experience: 15ms to flush 10K MACs in a node (1GHz MIPS Core)

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Issue2. Server Edge

Vswitch

NIC NIC

• Question: If a server has two or more NICs, how to find which port is first?

• vswitch: only vswitch to support All-Path• VEB: both VEB and vswitch to support All-Path• VEPA: only external switch to support All-Path

Vswitch

NIC

VEB

NIC

VEB

VEPA

NIC

Ext. switch

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Issue3. Load Balance

• Load balance is available in natural way because high load link tend not to be selected with queuing delay.

• Pros: zero-configuration load balance, no extra processing effort

• Cons: you cannot control load balance like SPB/ECMP

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Report on Proposal for AVB TG

• May 12, Thu, morning session @ AVB• Dr. Ibanez presented the materials as used in IW session

(Singapore and Santa Fe)• Questions and comments

– Any other metric than latency e.g. bandwidth?

– Path recovery time comparing with RSTP?

– Any broadcast storm occurred when link failed?

– What’s the status in IW session, any PAR created?

• AVB status– They try to solve by their own way, using SRP.

– Not only latency but also bandwidth can be used as metric

– Also redundant path can be calculated