[j-nsp] Segment Routing ( SPRING ) (James Bensley)

[Duane Grant]

On 5 March 2016 at 15:17, Jesper Skriver <jesper at skriver.dk> wrote:
>
>> On 05 Mar 2016, at 16:41, Saku Ytti <saku at ytti.fi> wrote:
>>
>> On 5 March 2016 at 15:22, Adam Vitkovsky <Adam.Vitkovsky at gamma.co.uk>
wrote:
>>>> (b) Are there any noticeable behavioral differences between SPRING and
>>>> LDP implementations?
>>>>
>>> Yes instead of label swap routers do label pop

I think that SR uses the same MPLS data plane, and uses at least push and
swap.
This preso is pretty good and has some examples:
http://conference.apnic.net/data/36/apnic36-segment-routing-santanu_v2s_1377667562.pdf

>SR can also use IPv6 and build stacks of IPv6 headers so not just MPLS
>label stacks (a-la service chaining).

>Also this is working more or less in IOS-XR (ASR9000). I've build a
>basic working topology on Cisco VIRL and it worked. Haven't any
>"proper" testing though as I've had no time of late.
>
>I don't know any Juniper kit that's running SR at present.

It looks like some SR made it into 15.1F5:


   - Support for IS-IS segment routing (PTX Series)—Starting with Junos OS
   Release 15.1F5, IS-IS segment routing support is enabled through MPLS.
   Currently, label advertisements are supported for IS-IS only. IS-IS creates
   an adjacency segment per adjacency, per level, and per address family (one
   each for IPv4 and IPv6). Junos OS IS-IS implementation allocates node
   segment label blocks in accordance with the IS-IS protocol extensions for
   supporting segment routing node segments and provides a mechanism to the
   network operator to provision an IPv4 or IPv6 address family node segment
   index. To configure segment routing, use the following configuration
   statements at the [edit protocols isis] hierarchy level:
      - no-advertise-adjacency-segment—Disable advertising of the adjacency
      segment on all levels for a specific interface.
      - node-segment—Enable source packet routing at all levels.
      - source-packet-routing—Enable the source packet routing feature.
      - use-source-packet-routing—Enable use of source packet routing node
      segment labels for computing backup paths for normal IPv4 or IPv6 IS-IS
      prefixes and primary IS-IS source packet routing node segments.



>James.