RBridge Aggregation Mingui Zhang, Donald Eastlake - - PowerPoint PPT Presentation

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RBridge Aggregation Mingui Zhang, Donald Eastlake - - PowerPoint PPT Presentation

RBridge Aggregation Mingui Zhang, Donald Eastlake zhangmingui@huawei.com RBridge Aggregation 1 Single AF: Loop Avoidance To avoid loops involving native frames, TRILL allows only a single Appointed Forwarder for one VLAN on a local link.


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SLIDE 1

RBridge Aggregation

Mingui Zhang, Donald Eastlake zhangmingui@huawei.com

1 RBridge Aggregation

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SLIDE 2

Single AF: Loop Avoidance

  • To avoid loops involving native frames, TRILL

allows only a single Appointed Forwarder for

  • ne VLAN on a local link.
  • RB2

RB1

Local Link Local Link

  • Single AF means single ingress & single egress

for a specific VLAN.

2 RBridge Aggregation

VLAN-x

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SLIDE 3

Purpose of Aggregation

  • Provide active/active multi-homing to a

specific VLAN on a local link

  • Increase the reliability of TRILL edge
  • Increase the access bandwidth of RBridge

campus

3 RBridge Aggregation

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SLIDE 4

RBridge Aggregation

  • Two RBridges use one

nickname, pseudonode nickname, to ingress frames.

Transit RBridge Campus

RBi

Transit RBridge Campus

RBi

  • Advertise virtual links

(e.g., RB1-RBv, RB2-RBv)

  • They can forward data

frame for VLAN-x at the same time (active-active).

4 RBridge Aggregation

VLAN-x

RB1 RB2 RB1 RB2

VLAN-x

RBv B1 B1

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SLIDE 5

Two Possible Issues

  • Traffic Duplication

– Multicast frames egressed by both aggregated members

Transit RBridge Campus Transit RBridge Campus

  • Forwarding Loop

– Multicast frames from the local link are egressed back to the local link by another aggregated member

RBridge Aggregation 5 RB1 RB2 RBv RB1 RB2 RBv

Traffic Duplication Forwarding Loop

B1 B1

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SLIDE 6

Link Aggregation [802.1AX] or Hashing

  • The access links of the bridge are configured

as link aggregation [802.1AX].

– A frame is transmitted by one link one time

  • Choose a single member using local hashing

– A frame goes through one RBridge one time – Current version of our draft adopt this solution

6 RBridge Aggregation

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SLIDE 7

Frame Processing: Known Unicast

  • Ingress

– Set the nickname to the pseudonoe nickname “RBv” – Receiver ingresses the frame to the TRILL campus

  • Egress

– Receiver egresses the frame to the local link

7 RBridge Aggregation

Only once Only once

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SLIDE 8

Frame Processing: Multicast

  • Ingress

– If hashing matches

  • Set the nickname to “RBv” and send it

– If not, drop it

Only once

– If not, drop it

  • Egress

– If hashing matches

  • send the frame

– If not, drop it

8 RBridge Aggregation

Only once

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SLIDE 9

Frame Processing: Unknown Unicast

  • Ingress

– The access bridge sends one copy of the frame with unknown unicast blocking technique – Aggregated RBridges treat the frame as unicast – Aggregated RBridges treat the frame as unicast

  • Egress

– Same as multicast egress

9 RBridge Aggregation

Only once Only once

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SLIDE 10

MAC Learning

  • MAC addresses of the aggregated RBridges

SHOULD be synchronized using ESADI.

  • Before a MAC address is got from another

aggregation member’s ESADI, frames destined to this MAC address will be sent as unknown unicast.

10 RBridge Aggregation

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SLIDE 11

Hashing Function Configuration

  • An aggregation member can only send

multicast frames with a specific hashing value.

– E.g., RB1 only sends multicast frames that the last bit of their source MAC is “0”. bit of their source MAC is “0”.

RBridge Aggregation 11

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SLIDE 12

Hashing under Link Failures

  • When a connection to one aggregation

member failed, the next member on the list takes the responsibility to send multicast frames for the aggregation. frames for the aggregation.

RBridge Aggregation 12

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SLIDE 13

Thanks!

13 RBridge Aggregation