What if you were to setup four BDIs running OSPF/MPLS across these two physical interfaces. Two BDIs per physical interface. Would that make ECMP work correctly using an ASR920?
We're going to be in the same boat soon too.. ASR920's on both sides with OSPF across two physical paths and worried about load sharing. Most of our traffic is MPLS xconnects traversing these links (licensed backhauls). On Wed, Aug 30, 2017 at 6:35 PM, CiscoNSP List <[email protected]> wrote: > AAh - Thank you James! So the ASR920 will not ECMP over 2 links, it > requires 4...that would explain the difference between egress/ingress (and > why the 920 is not working particularly well!) > > > Yes, this is ECMP, not LAG - So changing the load sharing algorithm can > only be done globally (As I tried to do it under the individual interfaces, > and was only presented with per dst as an option) > > > (config-if)#ip load-sharing ? > per-destination Deterministic distribution > > > So, changing globally will potentially cause a service disruption? (May > need to do this in maintenance window) - Do you suggest "include-ports" as > a possible candidate? > > > #ip cef load-sharing algorithm ? > include-ports Algorithm that includes layer 4 ports > original Original algorithm > tunnel Algorithm for use in tunnel only environments > universal Algorithm for use in most environments > > And yes, we are running MPLS over these links (But not a LAG as mentioned) > - So does your comment re MPLS hasting still apply to our setup, or only to > a LAG? > > > Thanks again for your response - Extremely helpful! > > > ________________________________ > From: cisco-nsp <[email protected]> on behalf of James > Bensley <[email protected]> > Sent: Thursday, 31 August 2017 6:43 AM > To: [email protected] > Subject: Re: [c-nsp] OSPF equal cost load balancing > > I think two layer ECMP links are being used here, both of which are in > the IGP. Are you running MPLS over these links too? > > The ME3600 is able to ECMP over any number of links as far as I know > (up to the max, which is 8 or 16) however I think the ASR920 will only > ECMP over 4 or 8 links (so not 2 as in your case). This could be the > problem here. > > Could you also try to change the CEF load balancing algorithm > (assuming this is ECMP and not LAG, this won't affect a LAG): > > ASR920(config)#ip cef load-sharing algorithm ? > include-ports Algorithm that includes layer 4 ports > original Original algorithm > tunnel Algorithm for use in tunnel only environments > universal Algorithm for use in most environments > > If it is a LAG then on the ASR920 try to adjust these options: > > ASR920(config)#port-channel load-balance-hash-algo ? > dst-ip Destination IP > dst-mac Destination MAC > src-dst-ip Source XOR Destination IP Addr > src-dst-mac Source XOR Destination MAC > src-dst-mixed-ip-port Source XOR Destination Port, IP addr > src-ip Source IP > src-mac Source MAC > > If you're running MPLS over the LAG the ASR920 can hash MPLS over the > LAG and the ASR920 should hash over 2 links just fine. > > Cheers, > James. > _______________________________________________ > cisco-nsp mailing list [email protected] > https://puck.nether.net/mailman/listinfo/cisco-nsp > cisco-nsp Info Page - puck.nether.net<https://puck. > nether.net/mailman/listinfo/cisco-nsp> > puck.nether.net > To see the collection of prior postings to the list, visit the cisco-nsp > Archives. Using cisco-nsp: To post a message to all the list members, send > ... > > > > archive at http://puck.nether.net/pipermail/cisco-nsp/ > _______________________________________________ > cisco-nsp mailing list [email protected] > https://puck.nether.net/mailman/listinfo/cisco-nsp > archive at http://puck.nether.net/pipermail/cisco-nsp/ > _______________________________________________ cisco-nsp mailing list [email protected] https://puck.nether.net/mailman/listinfo/cisco-nsp archive at http://puck.nether.net/pipermail/cisco-nsp/
