Nanog Folks:
Philip Matthews and I are co-authors on an active draft within the IETF related to IPv6 routing design choices. To ensure we are gathering sufficient data we are looking for an expanded set of input from operator forums as well (vs. just the v6ops IETF list). The draft is found here -(https://tools.ietf.org/html/draft-ietf-v6ops-design-choices).
We are looking for information on the IGP combinations people are running in their dual-stack networks. We are gathering this information so we can document in our draft which IGP choices are known to work well (i.e., people actually run this combination in production networks without issues). The draft will not name names, but just discuss things in aggregate: for example, "there are 3 large and 2 small production networks that run OSPF for IPv4 and IS-IS for IPv6, thus that combination is judged to work well".
If you have a production dual-stack network, then we would like to know which IGP you use to route IPv4 and which you use to route IPv6. We would also like to know roughly how many routers are running this combination. Feel free to share any successes or concerns with the combination as well.
We are looking particularly at combinations of the following IGPs: IS-IS, OSPFv2, OSPFv3, EIGRP.
If you run something else (RIP?) then we would also like to hear about this, though we will likely document these differently. [We suspect you run RIP/RIPng only at the edge for special situations, but feel free to correct us].
And if you have one of those modern networks that carries dual-stack customer traffic in a L3VPN or similar and thus don’t need a dual-stacked core, then please email us and brag ...
If you are on multiple lists at RIPE, NANOG or the IETF, we appologize for any redundant emails you may get (we are just attempting to reach the widest audience possible).
Philip Matthews
Victor Kuarsingh
If you have a production dual-stack network, then we would like to know
which IGP you use to route IPv4 and which you use to route IPv6.
in one network, both ospfs. in another is-is. i recommend the latter.
We would also like to know roughly how many routers are running this
combination.
lots
randy
If you have a production dual-stack network, then we would like to know
which IGP you use to route IPv4 and which you use to route IPv6.
in one network, both ospfs. in another is-is. i recommend the latter.
We would also like to know roughly how many routers are running this
combination.
why is the question /routers/ and not /networks/ ? (which is still
sort of nutty since your reasonable choices for 'dual stack capable'
are: ospf/ospf3 || isis)
Routers makes more sense to me than networks (IGP, so one network, right?)
Joe
that confuses me, the logic I mean...
I suppose in a single network I'd expect to see one igp for an address
family (ospf or ospfv3). Not "eastcoast devices do ospf (stodgy
bastards!) and westcoast goes isis!"
Think of scenarios where you have mergers/acquisitions where different portions of the now amalgamated network were designed differently and there may be too much pain or require too much time to redesign rather than bolt together and redistribute.
Sk.
But in that case, don't they usually say "The heck with it" and continue
using 2 separate ASN numbers?
Routers makes more sense to me than networks (IGP, so one network,
right?)
so you are thinking of a network where half the routers run is-is one
quarter ospf/ospfv2 and one quarter ospf/ripv3. right.
there was a very large provider that had one is-is leven-2 across many
bgp confederations.
there was a ....
At one time I had datacenter interiors that had no isis support. they
ran ospfv2 and to the extent that it was necessary in limited
application ospfv3. the datacenter border and the backbone used ISIS for
both adress families. routes were in general not redistributed between IGPs.
Think of scenarios where you have mergers/acquisitions where
different portions of the now amalgamated network were designed
differently and there may be too much pain or require too much time
to redesign rather than bolt together and redistribute.
But in that case, don't they usually say "The heck with it" and
continue using 2 separate ASN numbers?
we didn't take that path. we used separated igps (did not want to share
blood with yet to be trusted acquired engineers), and bgp confederation
so there was one external asn.
a useful transition strategy. but in that configuration, bgp at the
confed border is ebgp, not ibgp. this has interesting consequences on
timing of routing propagation, even with timers turned down.
see http://archive.psg.com/030226.apnic-flap.pdf
randy
I/we (Philip and I) attempted to keep the question as generic as possible, allowing folks to state the IGPs they use, in whichever combination or in some cases (as we can see), more complex deployments.
I would agree with statements form Joel earlier with respect to cases where early vendor support may have influenced some network zones (inside a given AS) to support a different IGP (his case of OSPFv3 for devices which lacked IS-IS support is one I did face a few years back as well in the DC with respect to Load balancing and Firewall devices).
The merger one was a new one for me, but it seems to reflect some peoples reality.
regards,
Victor K
a researcher i know and respect asked a bunch of ops what features that
used. the researcher finally said something similar to "operators seem
to actually use all those kinky knobs and protocols."
for any kink you can imagine, someone does it. there are operators who
have even deployed ipv6 
randy
see the other thread of the week, you are wrong sir! wrong!
At AS701/2/3 there were nominally 2k devices (way back when) using
ISIS for their igp for both v4 and v6 data... though the igp split on
as-boundaries.
hope that helps!
When we first were moving to IPv6 in the core network we evaluated IS-IS because it was what we were using for IPv4 and we would have preferred to run a single protocol for both. We had problems with running a mix of routers where some supported IPv6 and others did not. From what I recall, if any router did not support IPv6 then it wouldn't connect to a router running v6 and v4.
It's possible these were bugs and they were worked out later or just a messed up design in the lab, but we also like the idea of keeping IPv4 and IPv6 away from each other so if one is broken the other one might still work.
So we use OSPFv3 for IPv6 routing and IS-IS for IPv4 routing.
We use IS-IS dual-stack in the core,
and OSPFv2+OSPFv3 in the datacenters.
Roughly 100 routers in the IS-IS core, and
less than 2000 routers in the OSPFv2+OSPFv3
datacenters.
Matt
In such cases, BGP-LS may be a better approach, as that encourages more
sane filtering in the IGP than an IGP generally would.
Mark.
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At one time I had datacenter interiors that had no isis support. they
ran ospfv2 and to the extent that it was necessary in limited
application ospfv3. the datacenter border and the backbone used ISIS for
both adress families. routes were in general not redistributed between
IGPs.
We run Quagga on Anycast servers (DNS, NTP, TACACS+, e.t.c.) using
OSPFv2|v3, largely because Quagga's IS-IS support is terrible.
We have (restrictively) redistribute that into our IS-IS backbone, which
works great.
Wish we didn't have to do that, but it works well, and OSPF is stable in
Quagga.
Mark.
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It did for us - IS-IS here with a couple hundred routers (and growing),
as I mentioned to Victor and Philip when they posted this in another forum.
Single level (L2).
Mark.