Re: Segment Routing

[Matt Geary]

Hi Saku gotcha and I see most config examples are RSVP/SR-TE like, where in
most of the networks I have come across basic LDP is more than acceptable.

On Tue, May 22, 2018, 17:48 Saku Ytti  wrote:

> Hey Matt,
>
> > I guess my point is why go through the extra config to program labels for
> > each box when LDP does it for you? Why loose potential visibility to
> network
> > traffic? Cisco sales and marketing is digging huge into the SR game for
> > enterprise and SDWAN like backbone networking. They are touting about the
> > whole industry changing, but I'm not seeing it anywhere in the large
> network
> > or provider space. Hench my original question why SR over LDP? Seems SR
> is a
> > lot of extra config to give you all the program options for white box
> like
> > networking, when basic LDP in a Cisco variant works just fine.
>
> There isn't inherently anything you need to configure in SR, it's all
> implementation detail.
> Juniper requires you configure your 'index', but just as well 'index'
> could be inferred from your loopback0 or router-id.
>
> And indeed in your configuration generation where you generate your
> router-id, you can use static method to turn router-id into unique
> index and configure it once.
> Or you could ask vendor to implement feature to auto-assign index.
>
> Much like some devices can auto-assign unique RD to VRF, some require
> operator to assign them. Entirely implementation detail, not a valid
> argument between protocols.
>
>
> The upside of SR to LDP
>   - removal of entire protocol
>   - full-mesh visibility
>   - guaranteed IGP+Label sync
>
> The amount of configuration needed to do SR like LDP should be less
> than LDP. Confusion may arise by looking at SR examples, as SR can
> also be used like RSVP, which indeed is far more complex use-case.
>
> --
>   ++ytti
>

Re: Segment Routing

[Matt Geary]

I guess my point is why go through the extra config to program labels for
each box when LDP does it for you? Why loose potential visibility to
network traffic? Cisco sales and marketing is digging huge into the SR game
for enterprise and SDWAN like backbone networking. They are touting about
the whole industry changing, but I'm not seeing it anywhere in the large
network or provider space. Hench my original question why SR over LDP?
Seems SR is a lot of extra config to give you all the program options for
white box like networking, when basic LDP in a Cisco variant works just
fine.

On Tue, May 22, 2018, 16:19 Saku Ytti  wrote:

> Hey Steve,
>
> > the data plane behavior on LDP is swap oriented, while the data plane on
> SR
> > is pop oriented.  depending on the hardware capabilities in use this may
> > have (subtle) traffic engineering or diagnostic implications at a
> minimum.
> > folks will likely have to build tooling to address this.
>
> I think you're thinking of SR-TE, SR in normal LDP-like use case would be
> single
> egress label with swap on LSRs.
>
> Ingress PE would figure out label by using egress PE index as an
> offset to next-hop
> P's label range.
> Nexthop P would swap the label determining out label using same mechanism.
>
> I practice operators would configure same label range in every box, so
> swap would be
> from same label to same label. But that is purely due to operator
> configuration, and
> it's still swap.
>
> --
>   ++ytti
>

Re: Segment Routing

[Matt Geary]

SR as a replacement for LDP, but SR-LDP imterop is imteresting too. Do.you
have any experience with that?

On May 22, 2018 02:59, "dip" <diptanshu.si...@gmail.com> wrote:

Matt,

Just to clarify, Are you asking for SR and LDP interop or SR over LDP? Two
different things.

Thanks
Dip

On Fri, May 18, 2018 at 3:11 AM, Matt Geary <matt.ge...@gmail.com> wrote:

> Hello maillist anyone had any experience with segment routing and its
> performance over LDP? We are evaluating the option to move to SR over LDP
> so we can label switch across our Nexus L3 switching environment.
>
> Thanks
> Packet Plumber
>

-- 
Sent from iPhone

Re: Segment Routing

[Matt Geary]

Yeah Cisco rep commented that adding LDP to nexus would make ASR obsolete.
48x10g with LDP for $5-7k Yeah no brainer. Although on other point I am not
really seeing the value of SR to replace LDP on my backbone. With some
scripting and lots of software tools I can make it just like LDP, but why?
So break the ease of LDP just to get label switching on my hub core not
really seeing it, unless someone has done it and they are seeing the value.

On Tue, May 22, 2018, 10:14 Mark Tinka <mark.ti...@seacom.mu> wrote:

>
>
> On 22/May/18 10:06, Matt Geary wrote:
>
> Yes we are considering changing to SR on our backbone because LDP is not
> supported on the nexus switches. Although, we have no experience with SR
> and looks plainly simple but we loose some of the LSP path selection.
>
>
> Got you.
>
> I'm more curious about use-cases for folk considering SR, than SR itself.
>
> 4 years on, and I still can't find a reason to replace my LDP network with
> SR.
>
> Your use-case makes sense, as it sounds like Cisco deliberately left LDP
> out of your box, considering SR is in. But that's a whole other discussion
> :-)...
>
> Mark.
>

Re: Segment Routing

[Matt Geary]

Yes we are considering changing to SR on our backbone because LDP is not
supported on the nexus switches. Although, we have no experience with SR
and looks plainly simple but we loose some of the LSP path selection.

On Tue, May 22, 2018, 10:05 Mark Tinka <mark.ti...@seacom.mu> wrote:

>
>
> On 18/May/18 12:11, Matt Geary wrote:
>
> Hello maillist anyone had any experience with segment routing and its
> performance over LDP? We are evaluating the option to move to SR over LDP
> so we can label switch across our Nexus L3 switching environment.
>
>
> Is your use-case because you need label switching and the Nexus does not
> support LDP?
>
> Mark.
>

Segment Routing

[Matt Geary]

Hello maillist anyone had any experience with segment routing and its
performance over LDP? We are evaluating the option to move to SR over LDP
so we can label switch across our Nexus L3 switching environment.

Thanks
Packet Plumber