jwbensley+nanog at gmail.com
Thu Sep 17 08:00:16 UTC 2020
On 16 September 2020 23:51:03 CEST, Robert Raszuk <robert at raszuk.net> wrote:
>> If you want an IPv6 underlay for a network offering VPN services
>And what's wrong again with MPLS over UDP to accomplish the very same
>MPLS - just a demux label to a VRF/CE
>UDP with IPv6 header plain and simple
>+ minor benefit: you get all of this with zero change to shipping
>and software ... Why do we need to go via decks of SRm6 slides and new
>of protocols extensions ???
>> Please consider the TE mechanism described in
>> draft-bonica-6man-comp-rtg-hdr and the service labeling mechanism
>> in draft-bonica-6man-vpn-dest-opt. These can be deployed on a mix and
>> basis. For example can deploy:
>> - Draft-bonica-6man-vpn-dest-opt only, allowing traffic to follow
>> least-cost path from PE to PE.
>> - Deploy draft-bonica-6man-vpn-dest-opt only, using a legacy
>> (VXLAN, RFC 4797) to label services.
>> In all cases, the semantic of the IPv6 address is unchanged. There is
>> need to encode anything new in the IPv6 address.
MPLSoUDP lacks transport engineering features like explicit paths, FRR LFA and FRR rLFA, assuming only a single IP header is used for the transport abstraction . If you want stuff like TI-LFA (I assume this is supported in SRm6 and SRv6, but I'm not familiar with these, sorry if that is a false assumption) you need additional transport headers or a stack of MPLS labels encapped in the UDP header and then you're back to square one.
 I'm interested to hear if anyone has done any large scale MPLSoUDP work. Did you hack in this functionality with static egress interface entries/static routes pushed from a central controller for specific IPs reserve as "path" IPs?
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