10-13-2010 03:34 AM - edited 03-06-2019 01:29 PM
Tricky question:
In the scenario where we have a etherchannel with only one port and traffic is passing by it, when another physical port is put into the etherchannel, will all the traffic be"hashed" again and load-balanced by the algorithm over the 2 ports or will only new traffic be load-balanced and the "old" traffic will still only use the first port (will there be a timeout or something for this traffic) ?
Solved! Go to Solution.
10-13-2010 04:43 AM
Hello, As soon as you add a port to a etherchannel, the etherchannel "hashing bits" will be immediately load-balanced - which includes old and new traffic.
Etherchannel hashing has 8 bits.For any given flow, hashing result (referred as RBH) will be one of the values in the range of 0-7.
when you have only one port then all hashing bits mapped to that port.
Say, Gig 1/1 is the only port, then hashing bits 1111 1111 ==> FF
This means, traffic mapped to any RBH will be Tx by Gig1/1
As soon as you add another port, Say Gig1/2, then hashing bits will be:
Gig 1/1 ==> AA ==> 1010 1010 (traffic with RBH 1, 3, 5, and 7 will be sent via this port)
Gig 1/2 ==> 55 ==> 0101 0101 (traffic with RBH 0, 2, 4 and 6 will be sent via this port)
Hope this helps.
- Yogesh
10-13-2010 04:43 AM
Hello, As soon as you add a port to a etherchannel, the etherchannel "hashing bits" will be immediately load-balanced - which includes old and new traffic.
Etherchannel hashing has 8 bits.For any given flow, hashing result (referred as RBH) will be one of the values in the range of 0-7.
when you have only one port then all hashing bits mapped to that port.
Say, Gig 1/1 is the only port, then hashing bits 1111 1111 ==> FF
This means, traffic mapped to any RBH will be Tx by Gig1/1
As soon as you add another port, Say Gig1/2, then hashing bits will be:
Gig 1/1 ==> AA ==> 1010 1010 (traffic with RBH 1, 3, 5, and 7 will be sent via this port)
Gig 1/2 ==> 55 ==> 0101 0101 (traffic with RBH 0, 2, 4 and 6 will be sent via this port)
Hope this helps.
- Yogesh
Discover and save your favorite ideas. Come back to expert answers, step-by-step guides, recent topics, and more.
New here? Get started with these tips. How to use Community New member guide