Hi Gyan, I was talking about the use-case where we create two flex-algo’s and the desire is that they for example avoid congruent optical paths to avoid that a single fiber cut, would impact both streams. For some high value live-live streams or financials this may be an important service property. This type of flex-algo capability was a use-case about 1.5 a 2 years ago and caused the flex-algo to add exclude-srlg into the FAD to support such use-case.
The use-case was not about FRR, or RSVP-TE or anything similar. Advertising link properties is taken care of by the legacy and ASLA TE IGP attributes. The requested ‘avoid congruent optical paths’ use-case added the exclude-srlg subTLV within the flex-algo FAD, but unlike the EAG, the SRLG can theoretically cause overflow of 255 octet subTLV under certain (mostly theoretical) circumstance. I am in full agreement with Peter, that excluding 100s of SRLG is a something we will unlikely encounter, but then again, I see sometimes mythical oddness in use-case requests and I can not predict what requests future will bring. I am not asking for bigger or multiple SRLG subTLVs, but hope to find guidance to have implementation X behave identical/similar as implementation Y when such condition occurs. G/ From: Gyan Mishra <[email protected]> Sent: Thursday, March 10, 2022 5:05 AM To: Tony Li <[email protected]> Cc: Peter Psenak <[email protected]>; Van De Velde, Gunter (Nokia - BE/Antwerp) <[email protected]>; lsr <[email protected]> Subject: Re: [Lsr] New Version Notification for draft-pkaneria-lsr-multi-tlv-00.txt Gunter The use case for SRLG is only related to RSVP-TE FRR protection is my understanding. However, Flex Algo is only applicable to SR forwarding plane SR-MPLS and SRv6? Correct? RSVP-TE FRR SRLG protection application can be used in parallel to SR-MPLS or SRv6 but in that case they would be 3 different ASLA apps if used on the same link. For SR-MPLS, SR forwarding plane you could use RSVP-TE SRLG protection or SR-TE protection schemes. I don’t think the RSVP-TE FRR SRLG protection would apply to SR-TE protection to use the concept of SRLG with SR-MPLS with Flex Algo or would it apply. Kind Regards Gyan On Fri, Mar 4, 2022 at 1:03 PM Tony Li <[email protected]<mailto:[email protected]>> wrote: Peter, the combination is the (a) problem and that will be fixed. We are talking problem (b) only now. Ah, my apologies, I was unclear on the applicability of your statements. I'm not trying under-specify how to deal with overflow - we need to specify it, no disagreement there. I look forward to seeing a proposal. I propose allowing multiple FAD and concatenation of the contents. What I'm trying to see of we need to support the "merge" at FAD sub-TLV level. I’ll agree that that’s lower priority. I think we should, as a matter of completeness. Tony _______________________________________________ Lsr mailing list [email protected]<mailto:[email protected]> https://www.ietf.org/mailman/listinfo/lsr -- [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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