nanog mailing list archives
RE: why am i in this handbasket? (was Devil's Advocate - Segment Routing, Why?)
From: <adamv0025 () netconsultings com>
Date: Mon, 22 Jun 2020 08:06:24 +0100
But MPLS can be made flow driven (it can be made whatever the policy dictates), for instance DSCP driven… adam From: NANOG <nanog-bounces+adamv0025=netconsultings.com () nanog org> On Behalf Of Robert Raszuk Sent: Saturday, June 20, 2020 4:13 PM To: Masataka Ohta <mohta () necom830 hpcl titech ac jp> Cc: North American Network Operators' Group <nanog () nanog org> Subject: Re: why am i in this handbasket? (was Devil's Advocate - Segment Routing, Why?) The problem of MPLS, however, is that, it must also be flow driven, because detailed route information at the destination is necessary to prepare nested labels at the source, which costs a lot and should be attempted only for detected flows. MPLS is not flow driven. I sent some mail about it but perhaps it bounced. MPLS LDP or L3VPNs was NEVER flow driven. Since day one till today it was and still is purely destination based. Transport is using LSP to egress PE (dst IP). L3VPNs are using either per dst prefix, or per CE or per VRF labels. No implementation does anything upon "flow detection" - to prepare any nested labels. Even in FIBs all information is preprogrammed in hierarchical fashion well before any flow packet arrives. Thx, R.
there is the argument that switching MPLS is faster than IP; when the pressure points i see are more at routing (BGP/LDP/RSVP/whatever), recovery, and convergence.
Routing table at IPv4 backbone today needs at most 16M entries to be looked up by simple SRAM, which is as fast as MPLS look up, which is one of a reason why we should obsolete IPv6. Though resource reserved flows need their own routing table entries, they should be charged proportional to duration of the reservation, which can scale to afford the cost to have the entries. Masataka Ohta
Current thread:
- Re: why am i in this handbasket? (was Devil's Advocate - Segment Routing, Why?), (continued)
- Re: why am i in this handbasket? (was Devil's Advocate - Segment Routing, Why?) Masataka Ohta (Jun 23)
- BGP flooding Robert Raszuk (Jun 23)
- Re: why am i in this handbasket? (was Devil's Advocate - Segment Routing, Why?) Mark Tinka (Jun 21)
- Re: why am i in this handbasket? (was Devil's Advocate - Segment Routing, Why?) Masataka Ohta (Jun 22)
- Re: why am i in this handbasket? (was Devil's Advocate - Segment Routing, Why?) Mark Tinka (Jun 22)
- Re: why am i in this handbasket? (was Devil's Advocate - Segment Routing, Why?) Randy Bush (Jun 22)
- Re: why am i in this handbasket? (was Devil's Advocate - Segment Routing, Why?) Fletcher Kittredge (Jun 23)
- Re: why am i in this handbasket? (was Devil's Advocate - Segment Routing, Why?) Masataka Ohta (Jun 23)
- RE: why am i in this handbasket? (was Devil's Advocate - Segment Routing, Why?) adamv0025 (Jun 22)
- Re: why am i in this handbasket? (was Devil's Advocate - Segment Routing, Why?) Robert Raszuk (Jun 21)
- RE: why am i in this handbasket? (was Devil's Advocate - Segment Routing, Why?) adamv0025 (Jun 22)
- Re: why am i in this handbasket? (was Devil's Advocate - Segment Routing, Why?) Masataka Ohta (Jun 22)
- RE: why am i in this handbasket? (was Devil's Advocate - Segment Routing, Why?) adamv0025 (Jun 22)
- Re: why am i in this handbasket? (was Devil's Advocate - Segment Routing, Why?) Mark Tinka (Jun 22)
- Re: why am i in this handbasket? (was Devil's Advocate - Segment Routing, Why?) Masataka Ohta (Jun 23)
- Re: why am i in this handbasket? (was Devil's Advocate - Segment Routing, Why?) Mark Tinka (Jun 21)
- Re: why am i in this handbasket? (was Devil's Advocate - Segment Routing, Why?) Robert Raszuk (Jun 20)
- Re: why am i in this handbasket? (was Devil's Advocate - Segment Routing, Why?) Mark Tinka (Jun 21)
- Re: why am i in this handbasket? (was Devil's Advocate - Segment Routing, Why?) Mark Tinka (Jun 21)
- Re: Devil's Advocate - Segment Routing, Why? Masataka Ohta (Jun 19)
- Re: Devil's Advocate - Segment Routing, Why? Robert Raszuk (Jun 19)