The link bandwidth community has been implemented by Cisco and deployed by our customers for several years. Polarization of flows in multipath is a well known problem, but it hasn't deterred people from using it.
Regards, Jakob. From: BESS <[email protected]> On Behalf Of Gyan Mishra Sent: Tuesday, May 25, 2021 12:24 AM To: Satya Mohanty (satyamoh) <[email protected]> Cc: [email protected] Subject: Re: [bess] Request discussion on Cumulative Link Bandwidth Draft Hi Satya I read the draft and have a few questions. IPv4 does not support per flow per packet load balancing as all packets belonging to the same flow must hash to the same path to prevent out of order packets and thus is subject to polarization of flows as high bandwidth flows may hash to the same path and low bandwidth flows as well to the same path resulting in very uneven load balancing. Do to this issue it does not make either iBGP or eBGP can really benefit from link bandwidth extended community weight based load sharing. IPV6 flow label RFC 6437 stateless locally significant 5-tuple header hash generated 20 byte key input to hash function results in uniform 50/50 load balancing over EGP or IGP ECMP paths. I think it maybe a good idea to reference the IPv4 polarization issue with flow based load balancing and that only with IPv6 flow label can true 50/50 uniform load balancing be achieved. I noticed that the normative draft referenced was adopted but has not progressed. https://datatracker.ietf.org/doc/draft-ietf-idr-link-bandwidth/ Has the draft been implemented by Cisco or any other vendors ? Kind Regards Gyan On Sat, May 22, 2021 at 11:38 AM Satya Mohanty (satyamoh) <[email protected]<mailto:[email protected]>> wrote: Hi all, On behalf of all the authors, we request a discussion of the draft https://datatracker.ietf.org/doc/html/draft-mohanty-bess-ebgp-dmz-03 and subsequent WG adoption. This draft extends the usage of the DMZ link bandwidth to scenarios where the cumulative link bandwidth needs to be advertised to a BGP speaker. Additionally, there is provision to send the link bandwidth extended community to EBGP speakers via configurable knobs. Please refer to section 3 and 4 for the use cases. This feature has multiple-vendor implementations and has been deployed by several customers in their networks. Best Regards, --Satya _______________________________________________ BESS mailing list [email protected]<mailto:[email protected]> https://www.ietf.org/mailman/listinfo/bess -- [http://ss7.vzw.com/is/image/VerizonWireless/vz-logo-email]<http://www.verizon.com/> Gyan Mishra Network Solutions Architect Email [email protected]<mailto:[email protected]> M 301 502-1347
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