Service Providers

pmoyer

IETF 86 Recap of SP Related Activities

by pmoyer on ‎04-04-2013 03:19 PM (162 Views)

I recently returned from IETF 86  and would like to update the folks in this community with a brief synopsis of the event. Overall, it was a very well attended, interactive and relevant event! But I think that’s pretty much the norm these days, particularly with all the interest in SDN related technologies and use cases. I will post a separate blog in our SDN community on the SDN related IETF activities, so please go there for that update. In this blog, I will focus on IETF activities related to service providers.

MPLS

The MPLS WG items included many different things and I will lump the L2VPN, L3VPN, and PWE3 WG items all under the heading of MPLS.

I’ll start off with the discussion around IPv6 in MPLS networks. While we all know that there has been some interest and IETF standards work in the area of MPLS/IPv6, it has yet to garner much real deployment interest. Techniques for providing IPv6 over IPv4-based MPLS networks, such as 6PE and 6VPE, have solved some of the issues with IPv6 and MPLS. However, it appears the IETF community is now getting behind full IPv6 support in MPLS. This would include native IPv6 LDP and RSVP-TE support. Some folks believe that although full IPv6 MPLS networks may not be needed for another 3-5 years, the IETF community should get on board now and start officially driving this. The MPLS WG will start formally tracking progress in this area, as it’s deemed important work.

Entropy labels to improve load balancing in MPLS networks was briefly discussed and this appears to be a done deal in terms of standards (RFC 6790) and having broad community support and consensus.

TRILL over Pseudo-Wires was discussed in the PWE3 WG. This is cool stuff and appears to have some degree of consensus. This basically would allow a TRILL domain in one data center to have layer-2 connectivity to another TRILL domain in another data center.

A similar topic of VXLAN over L2 VPNs was discussed in the L2VPN WG. This would provide a layer-2 MPLS connection between VXLAN or NVGRE logical overlay networks. This is also a pretty cool use case and this appears to be a needed solution if VXLAN/NVGRE solutions become more widely deployed in data centers. A somewhat related topic was discussed on how Ethernet VPNs (E-VPNs) could be leveraged to provide a data center overlay solution. In this context, E-VPNs are based on MPLS technologies. While this solution revolves around Network Virtualization Overlays, it was discussed in the L2VPN WG due to it leveraging MPLS technologies. This Internet Draft was also discussed in the NVO3 WG.

Interesting work on MPLS forwarding compliance and performance requirements was discussed in the different MPLS WGs. This work intends to document the MPLS forwarding paradigm for the perspective of the MPLS implementer, MPLS developer and MPLS network operator. Very useful work!

In the L3VPN WG, there were quite a few IDs that overlap with the NVO3 WG and data center overlay technologies. The general support for MPLS-based solutions for data center overlay architectures appears to be gathering momentum. From a high level, this does make sense as MPLS VPN technologies provide a logical network overlay in the wide area of service provider networks. As data center overlay architectures evolve, why not leverage this work and experience? I will discuss more on this topic in my SDN community blog.

To wrap up the MPLS activities; there were a number of other MPLS-related developments and enhancements that I won’t go into detail about here.  Areas such as P2MP LSPs, special purpose MPLS label allocations, OAM, and additional functionality for advertising MPLS labels into the IGP (like an enhanced “forwarding adjacency”) were all discussed and are progressing at various stages though the IETF standards process.

Another WG that generated a fair amount of activity and interest is PCE. This is also an area of IETF work that is somewhat related to the SDN solution space. This WG is focused on how to enhance traffic-engineering decisions in MPLS networks. PCE functionality would “recommend” traffic-engineered LSPs for the network but would not be responsible for the actual instantiation of those LSPs into the network. That would be done by another function; and is deemed outside the scope of the PCE WG.

The WG agreed to make the PCE MIB “read-only”. This makes sense since the MIB is not a good place to implement PCE functionality. They also discussed P2MP LSPs, Service aware LSPs and even the support of wavelength switched optical networks. They also agreed that “Stateful” PCE was indeed in scope and in the charter.

Routing

Regarding the various Routing WGs (such as OSPF, ISIS, RTGWG, SIDR, and IDR), here is the recap.

Overall, nothing really ground breaking to report on in the area of routing activity at this IETF. One topic worth a mention is the North-bound distribution of link-state and TE routing information using BGP. This area is somewhat related to the SDN solution space, as it could provide upper layer applications (such as ALTO or PCE) the knowledge of link-state topology state from the network. This would allow those applications to make more intelligent traffic-engineering decisions.

Another area of routing that is interesting to mention is having the ability to make routing decisions based upon additional link-state metric information; such as latency, jitter and loss.  This seems like a very logical evolution of IP routing.

And to wrap up the routing activity; as expected, the security of inter-domain routing continues to generate lots of interest. It was interesting that immediately after the IETF, there was a paper published by Boston University on the security implications of the Resource Public Key Infrastructure (RPKI) being discussed on the SIDR mailing list. This paper seems to re- ignite some of the controversy around secure routing.

I2RS was also very well represented and generated lots of interesting dialogue and debate.

This WG is fairly new. The primary goal of this WG is to provide a real-time interface into the IP routing system. This interface will not only provide a configuration and management capability into the routing system, but will also allow the retrieval of useful information from the routing system. Quite a bit of the discussion was centered around what type of state information needs to be injected into the routing system, what type of state information should be extracted from the routing system, and interesting enough, what specifically is the “routing system”. The routing system is generally understood to be the Routing Information Base (RIB) in IP routers but there was a good amount of debate on exactly what constitutes a RIB, what information does it hold and what might the interface to this RIB look and behave like. It appears this WG may have taken a step back to re-group and get more focused before moving on to solutions too rapidly.

There were five use case drafts that were presented and discussed. So, while this WG may have taken a step back to more clearly understand and define the problem space, they are also continuing to move forward with relevant use case definitions and then onward to solutions.

So, that wraps up this short update on the IETF 86 SP related activities. I should mention before closing that the I2RS WG intends to hold an interim meeting after the ONS event in April, so if you are attending the ONS event you may want to attend the I2RS interim meeting as well.