Ethernet Switching
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Regular Visitor
tcalis
Posts: 9
Registered: ‎08-23-2010
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Link aggregation hashing -> will it take the local port?

Hi,

 

Another one we have been discussing between colleagues a while ago:

 

Imagine:  VC with two members

Two devices (server or switch) connected with a LAG to both members.

Device A has sent a packet on its first link of the LAG, with destination device B

 

 

 

Then my question:

* will the member that received the packet send it always out via his direct link to device B

   (take local LAG port)

or

* there is a possibility that the packet will be sent out to the other member (on VCP or fiber) and then to device B

  (because the hashing algorithm could decide that the packet should be on the certain port of the LAG, which could be on another member)

 

 

 

And even more difficult: how can we verify this?

 

KR,

 

 Thomas

 

Juniper Employee
DHawley
Posts: 6
Registered: ‎02-20-2009

Re: Link aggregation hashing -> will it take the local port?

On the EX4200 VC, the egress port is determined by the ingress hash, so the data could exit either a local port or a port on another VC member.

Regular Visitor
tcalis
Posts: 9
Registered: ‎08-23-2010
0

Re: Link aggregation hashing -> will it take the local port?

Thanks, this information is valuable when making a the network design.

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