Cisco Support Community
cancel
Showing results for 
Search instead for 
Did you mean: 
Announcements

Welcome to Cisco Support Community. We would love to have your feedback.

For an introduction to the new site, click here. If you'd prefer to explore, try our test area to get started. And see here for current known issues.

Bronze

Difference between Asymmertic VS. Symmetric routing

Can someone provide an explanation of the differences in a fully redundant layer 3 environment when dealing with Asymmertic Verses Symmetric?

thanks Frank

  • Other Network Infrastructure Subjects
1 REPLY
New Member

Re: Difference between Asymmertic VS. Symmetric routing

Asymmetric verses Symmetric just refers to the paths that data takes, round trip. With redundant design traffic flows may follow two or more paths. The packets travelling from A to B may follow a different path than packets travelling back from B to A. In most cases this is of no particular concern. In some cases a high degree of determinism may be desired.

Routing protocol metrics can be tuned to ensure that packets leaving a building block follow the same path as packets returning to the building block. For example: Packets flow from station A.1 on VLAN A through its default gateway which is Layer 3 switch X. On Layer 3 switch X the routing metric on interface VLAN A is adjusted to make this path more favorable than the alternate return path through switch Y. If OSPF is the routing protocol, the interface cost metric is adjusted. If EIGRP is the routing protocol, the interface delay metric is adjusted. And so forth.

8412
Views
4
Helpful
1
Replies
This widget could not be displayed.