Hey Jason and Tony, thanks for chiming in. After following up with my team, we ended up getting all sorted out. Originally, nobody my colleague spoke with could find the circuit or figure out how to route the support request. After contacting our account manager, everything ended up OK. He provided us with the circuit IDs and support contact info we needed.
Aside from the campus TV service, we have about 2 dozen locations with Comcast CBCI service where we provide SDWAN support. We also have hundreds of work-from-home users with Xfinity home internet. Having their traffic reach the main campus network via this circuit is great. It’s better than having the traffic go out to another provider and then back to our network. Based on Stephen’s original question about sending the no-export community, I don’t know if having customer reachability was originally intended for these circuits, but it does work and I hope it can continue to work that way. It seems like an all-around good thing for your customers. -- Bryan Ward Lead Network Engineer Dartmouth College Network Services [email protected]<mailto:[email protected]> Scheduling a meeting? I prefer Zoom. From: Livingood, Jason <[email protected]> Sent: Friday, May 16, 2025 1:56 PM To: North American Network Operators Group <[email protected]> Cc: Stephen Griffin <[email protected]>; Bryan Ward <[email protected]>; Tauber, Tony <[email protected]> Subject: Re: Xfinity on Campus Jason from Comcast here… If there are other things you think are valuable to do with these connections or would like them configured in a different way – we’re all ears. Just email Tony (cc’d) and I off-list – and others reading on NANOG using this service are welcome to do the same. Have a nice weekend, Jason From: Bryan Ward via NANOG <[email protected]<mailto:[email protected]>> Date: Thursday, May 15, 2025 at 15:20 To: North American Network Operators Group <[email protected]<mailto:[email protected]>> Cc: Stephen Griffin <[email protected]<mailto:[email protected]>>, Bryan Ward <[email protected]<mailto:[email protected]>> Subject: RE: Xfinity on Campus I've got one of these circuits too, and it's very strange how they handle them internally. From Comcast's point of view, these circuits don't even exist! They're not configured the same way as their "customers" circuits are. That means, calling for support for them is next to impossible... The goal of the circuit is to just provide IPTV traffic and nothing else. But, as you've been suggesting, you can adjust the BGP communities to use it for other purposes, such as advertising to their customers within their AS or even using the circuit for transit... I'd caution against this, as the commit rate is fairly low from what I've experienced, but it does work. -- Bryan Ward Lead Network Engineer Dartmouth College Network Services -----Original Message----- From: Eric C. Miller via NANOG <[email protected]<mailto:[email protected]>> Sent: Wednesday, May 14, 2025 4:00 PM To: North American Network Operators Group <[email protected]<mailto:[email protected]>> Cc: Stephen Griffin <[email protected]<mailto:[email protected]>>; Eric C. Miller <[email protected]<mailto:[email protected]>> Subject: Re: Xfinity on Campus I think Brian may have touched on this earlier in the thread, but a dirty way to accomplish would be sending to AS7922 your de-aggregated /24s with the noexport community. Send your aggregates(> /24) to your transit provider(s). If a AS7922 customer is default-free, they'd find you through your transit, if they default through AS7922, they reach you there. Path asymmetry is still a concern on both sides though. I concur with the earlier statement about resolving through your customer rep. AS7922+Customers feels more natural while still maintaining their ability to later sell you transit. Eric ________________________________ From: John van Oppen via NANOG <[email protected]<mailto:[email protected]>> Sent: Wednesday, May 14, 2025 2:24 PM To: North American Network Operators Group <[email protected]<mailto:[email protected]>> Cc: Stephen Griffin <[email protected]<mailto:[email protected]>>; John van Oppen <[email protected]<mailto:[email protected]>> Subject: RE: Xfinity on Campus No export is pretty obviously the wrong choice here, what you want is announce to customers only. -----Original Message----- From: Christopher Morrow via NANOG <[email protected]<mailto:[email protected]>> Sent: Wednesday, May 14, 2025 9:41 AM To: North American Network Operators Group <[email protected]<mailto:[email protected]>> Cc: Stephen Griffin <[email protected]<mailto:[email protected]>>; Christopher Morrow <[email protected]<mailto:[email protected]>> Subject: Re: Xfinity on Campus I'd guess that Stephen already checked the looking-glass at: ssh [email protected]<mailto:[email protected]> and validated that the prefix(s) in question are marked no-export... I suspect that a university also brings their own IP and ASN to the party, so seeing which prefixes have which communities is also something Stephen's done before asking the original question. yea... we can't (unless we are also comcast-campus-customers) know the contract particulars, but the question at the end seems reasonable. I'd suspect the overall assumption in the relationship is that the prefixes seen on 7922 from the neighbors are equality visible to all folks that default to comcast's network? perhaps this is a situation where: "access to the comcast eyeball set" is the goal of the relationship not 'access to ALL comcast customers' ? -chris On Wed, May 14, 2025 at 11:3 AM Brian Turnbow via NANOG <[email protected]<mailto:[email protected]>> wrote: > > Hi Stephen > > It really depends on the network you are advertising. > Say for example you are advertising a /24 or /48 that is part of a > block being advertised directly by 7922, or maybe the university's AS. > In this case even without announcing your netblock outside of 7922 > they will still be receiving the traffic via their announcement. so no > blackholing and traffic would still be coming in from the customers to you. > You can check this via looking glasses /route servers etc Your logic > would apply only to a unique netblock that is covered by another > announcement. > > HTH > Brian > > > > Brian Turnbow > +39 02 6706800 > [image: CDLAN SPA] > [image: CDLAN SPA] > <https://urldefense.com/v3/__https://www.cdlan.it/*__;Lw!!CQl3mcHX2A!Cywp7UeJolghnl4dl2gNpoJ8R93mv7FvLnBWvBa64tdXKRK3FCrw_XaaK0db6DtWXQUICljwHzt9ImMkFjYSGRnlSQ$ > > <https://urldefense.com/v3/__https:/www.cdlan.it/*__;Lw!!CQl3mcHX2A!Cywp7UeJolghnl4dl2gNpoJ8R93mv7FvLnBWvBa64tdXKRK3FCrw_XaaK0db6DtWXQUICljwHzt9ImMkFjYSGRnlSQ$%20> > > | [image: CDLAN SPA - > LinkedIn] > <https://urldefense.com/v3/__https://it.linkedin.com/company/cdlan__;!!CQl3mcHX2A!Cywp7UeJolghnl4dl2gNpoJ8R93mv7FvLnBWvBa64tdXKRK3FCrw_XaaK0db6DtWXQUICljwHzt9ImMkFjYGuaqG6w$ > > <https://urldefense.com/v3/__https:/it.linkedin.com/company/cdlan__;!!CQl3mcHX2A!Cywp7UeJolghnl4dl2gNpoJ8R93mv7FvLnBWvBa64tdXKRK3FCrw_XaaK0db6DtWXQUICljwHzt9ImMkFjYGuaqG6w$%20> > > > > > > Il giorno mer 14 mag 2025 alle ore 17:09 Stephen Griffin via NANOG < > [email protected]<mailto:[email protected]>> ha scritto: > > > So, I currently work for a university that offers Xfinity on Campus > > for our students. As part of that, we receive essentially peering.. with a > > twist... > > it is actually configured more like a normal customer. > > > > We're required to send 7922:999, which is essentially 7922's no-export. > > However, 7922:888 (7922+customers), seems like the better choice, > > while still respecting the goal of not providing transit. > > > > The former makes it such that 7922 doesn't advertise our prefixes to > > their BGP customers, which can lead to blackholes if their customer > > is default-free and their other provider(s) have an outage, or if > > the customer is doing link (but not provider) redundancy with BGP. > > It also means that billable traffic from xfinity customers to us is > > actually driven away from 7922, which would seem to not be in 7922's > > best interest (maybe folks no longer bill on usage?). > > > > no-export and its ilk just seems like the wrong choice in nearly > > every case, but I thought I would check myself with the assembled. > > > > Cheers, > > Stephen Griffin > > _______________________________________________ > > NANOG mailing list > > > > https://urldefense.com/v3/__https://lists.nanog.org/archives/list/[email protected]/message/__;!!CQl3mcHX2A!Cywp7UeJolghnl4dl2gNpoJ8R93mv7FvLnBWvBa64tdXKRK3FCrw_XaaK0db6DtWXQUICljwHzt9ImMkFjZOTgHNHw$<https://urldefense.com/v3/__https:/lists.nanog.org/archives/list/[email protected]/message/__;!!CQl3mcHX2A!Cywp7UeJolghnl4dl2gNpoJ8R93mv7FvLnBWvBa64tdXKRK3FCrw_XaaK0db6DtWXQUICljwHzt9ImMkFjZOTgHNHw$> > > NBQIF6L6YZEGWGY7WAHJNKQT7ISVTVAJ/ > > > _______________________________________________ > NANOG mailing list > https://urldefense.com/v3/__https://lists.nanog.org/archives/list/[email protected]/message/ST__;!!CQl3mcHX2A!Cywp7UeJolghnl4dl2gNpoJ8R93mv7FvLnBWvBa64tdXKRK3FCrw_XaaK0db6DtWXQUICljwHzt9ImMkFjaOxxeKHA$<https://urldefense.com/v3/__https:/lists.nanog.org/archives/list/[email protected]/message/ST__;!!CQl3mcHX2A!Cywp7UeJolghnl4dl2gNpoJ8R93mv7FvLnBWvBa64tdXKRK3FCrw_XaaK0db6DtWXQUICljwHzt9ImMkFjaOxxeKHA$> > GC5JQCQO7R7T7MO3C4WVB57MR2WZMY/ _______________________________________________ NANOG mailing list https://urldefense.com/v3/__https://lists.nanog.org/archives/list/[email protected]/message/6KG5YOZNZ6RC7FJH2IUFUHVYDWGIXHZP/__;!!CQl3mcHX2A!Cywp7UeJolghnl4dl2gNpoJ8R93mv7FvLnBWvBa64tdXKRK3FCrw_XaaK0db6DtWXQUICljwHzt9ImMkFjaN_fYlsA$<https://urldefense.com/v3/__https:/lists.nanog.org/archives/list/[email protected]/message/6KG5YOZNZ6RC7FJH2IUFUHVYDWGIXHZP/__;!!CQl3mcHX2A!Cywp7UeJolghnl4dl2gNpoJ8R93mv7FvLnBWvBa64tdXKRK3FCrw_XaaK0db6DtWXQUICljwHzt9ImMkFjaN_fYlsA$> _______________________________________________ NANOG mailing list https://urldefense.com/v3/__https://lists.nanog.org/archives/list/[email protected]/message/5JX56YQMCC2KJFM5PJHML4EIALGFKS4D/__;!!CQl3mcHX2A!Cywp7UeJolghnl4dl2gNpoJ8R93mv7FvLnBWvBa64tdXKRK3FCrw_XaaK0db6DtWXQUICljwHzt9ImMkFjbcl8fnbw$<https://urldefense.com/v3/__https:/lists.nanog.org/archives/list/[email protected]/message/5JX56YQMCC2KJFM5PJHML4EIALGFKS4D/__;!!CQl3mcHX2A!Cywp7UeJolghnl4dl2gNpoJ8R93mv7FvLnBWvBa64tdXKRK3FCrw_XaaK0db6DtWXQUICljwHzt9ImMkFjbcl8fnbw$> _______________________________________________ NANOG mailing list https://urldefense.com/v3/__https://lists.nanog.org/archives/list/[email protected]/message/YK4AYYV7KNCWQ6JR4UVBQXEKVVRXIEET/__;!!CQl3mcHX2A!Cywp7UeJolghnl4dl2gNpoJ8R93mv7FvLnBWvBa64tdXKRK3FCrw_XaaK0db6DtWXQUICljwHzt9ImMkFjbfnR5MsQ$<https://urldefense.com/v3/__https:/lists.nanog.org/archives/list/[email protected]/message/YK4AYYV7KNCWQ6JR4UVBQXEKVVRXIEET/__;!!CQl3mcHX2A!Cywp7UeJolghnl4dl2gNpoJ8R93mv7FvLnBWvBa64tdXKRK3FCrw_XaaK0db6DtWXQUICljwHzt9ImMkFjbfnR5MsQ$> _______________________________________________ NANOG mailing list https://urldefense.com/v3/__https://lists.nanog.org/archives/list/[email protected]/message/26SNFNKCYLWKCANBE34FL7JL6B24H72R/__;!!CQl3mcHX2A!Cywp7UeJolghnl4dl2gNpoJ8R93mv7FvLnBWvBa64tdXKRK3FCrw_XaaK0db6DtWXQUICljwHzt9ImMkFjb0ltAjrQ$<https://urldefense.com/v3/__https:/lists.nanog.org/archives/list/[email protected]/message/26SNFNKCYLWKCANBE34FL7JL6B24H72R/__;!!CQl3mcHX2A!Cywp7UeJolghnl4dl2gNpoJ8R93mv7FvLnBWvBa64tdXKRK3FCrw_XaaK0db6DtWXQUICljwHzt9ImMkFjb0ltAjrQ$> _______________________________________________ NANOG mailing list https://lists.nanog.org/archives/list/[email protected]/message/JW6EUT7MEOSEZ3BBRQ45IAU2ZMKUSTQR/
