Hi Tony and Acee, Thanks a lot for your valuable comments and insights.
Tony's understanding is right, it is based on the case where someone has multiple VLANs over one link between two routers. As Acee mentioned, there are many cases that a router establishes several links with another router by several sub-interfaces in the practical network deployment. However, a sub-interface does not have its own independent bandwidth and utilization information, its bandwidth and utilization information is just copied from their parent physical interface. When a remote device want to do load balancing based on the available bandwidth information, it can not know that several links are sharing the same physical bandwidth. This may lead to an unbalanced load, even result in packet loss when the traffic on a physical interface exceeds it max bandwidth. Therefore, this document propose extensions to IGP to advertise the relationship between a physical interface and its sub-interfaces. This information is valuable for load balancing in the head end. Best regards Li > -----邮件原件----- > 发件人: Acee Lindem <[email protected]> > 发送时间: 2026年3月2日 20:28 > 收件人: Tony Li <[email protected]> > 抄送: zhangli (CE) <[email protected]>; lsr <[email protected]>; > [email protected] > 主题: Re: [Lsr] New Version Notification for > draft-zl-lsr-igp-sub-interface-relationship-00.txt > > Hi Zhang, Tony, > > > On Mar 2, 2026, at 2:10 AM, Tony Li <[email protected]> wrote: > > > > > > Hi Zhang Li, > > > > Perhaps I’m not understanding the problem that you’re trying to solve. > > It seems to me that what you’re suggesting is that we create a special > > encoding to handle the case where someone has multiple VLANs over one > > link between two routers. Is that correct? Why would anyone want to > > do that? I > > This is a common way to include an interface in multiple areas in OSPFv2. I > expect it is used in OSPFv3 as well since people don't know how to configure > different Instance IDs. > > > > dislike adding hair to the protocol over a situation that should not exist. > > I haven't read the draft but I don't see why it makes any difference to the > IGPs > and agree. > > Thanks, > Acee > > > > > > Regards, > > Tony > > > > > >> On Mar 1, 2026, at 6:56 PM, zhangli (CE) - zhangli344=40huawei.com at > dmarc.ietf.org <[email protected]> wrote: > >> > >> Dear all, > >> > >> A new document draft-zl-lsr-igp-sub-interface-relationship-00 has been > submitted. This draft introduces extensions to IGP, allowing a network device > to > advertise the relationship between a physical interface and its > sub-interfaces. > These extensions enable the links based on sub-interfaces to participate in > the > alternative paths for load balancing. > >> > >> Links for the draft is as below. > >> > >> https://datatracker.ietf.org/doc/draft-zl-lsr-igp-sub-interface-relat > >> ionship/ > >> > >> Looking forward to your review and comments. > >> > >> Best regards > >> Li > >> -----邮件原件----- > >> 发件人: [email protected] <[email protected]> > >> 发送时间: 2026年2月28日 17:12 > >> 收件人: lichenxi (A) <[email protected]>; Dongjie (Jimmy) > >> <[email protected]>; zhangli (CE) <[email protected]> > >> 主题: New Version Notification for > >> draft-zl-lsr-igp-sub-interface-relationship-00.txt > >> > >> A new version of Internet-Draft > >> draft-zl-lsr-igp-sub-interface-relationship-00.txt has been successfully > submitted by Li Zhang and posted to the IETF repository. > >> > >> Name: draft-zl-lsr-igp-sub-interface-relationship > >> Revision: 00 > >> Title: IGP Extensions for Sub-interface Relationship Information > >> Date: 2026-02-28 > >> Group: Individual Submission > >> Pages: 8 > >> URL: > https://www.ietf.org/archive/id/draft-zl-lsr-igp-sub-interface-relationship-00.txt > >> Status: > https://datatracker.ietf.org/doc/draft-zl-lsr-igp-sub-interface-relationship/ > >> HTML: > https://www.ietf.org/archive/id/draft-zl-lsr-igp-sub-interface-relationship-00.ht > ml > >> HTMLized: > >> https://datatracker.ietf.org/doc/html/draft-zl-lsr-igp-sub-interface- > >> relationship > >> > >> > >> Abstract: > >> > >> This document extends ISIS and OSPF, allowing a network device to > >> advertise the relationship between a physical interface and its sub- > >> interfaces. This extension enables the links based on sub-interfaces > >> to participate in the alternative paths for load balancing in SRv6 BE > >> bandwidth polling. > >> > >> > >> > >> The IETF Secretariat > >> > >> > >> _______________________________________________ > >> Lsr mailing list -- [email protected] > >> To unsubscribe send an email to [email protected] > > > > _______________________________________________ > > Lsr mailing list -- [email protected] > > To unsubscribe send an email to [email protected] _______________________________________________ Lsr mailing list -- [email protected] To unsubscribe send an email to [email protected]
