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Optical/IP

MPLS Gets the Management Blues

As carriers move to the converged Internet Protocol (IP) / Multiprotocol Label Switching (MPLS) network, they still face the practical hurdle of operations, administration, and maintenance (OAM) -– functions they're accustomed to having. But the quest to add OAM to MPLS has pitted equipment vendors against their carrier customers in an odd sort of standards battle.

Equipment vendors were slow to answer carriers' calls for OAM, and the Internet Engineering Task Force (IETF) even rejected early proposals to work on MPLS OAM. So the carriers took matters into their own hands last year, drafting standards with the International Telecommunication Union, Standardization Sector (ITU-T).

News of the ITU standards jolted equipment vendors into action, and they've begun submitting proposals with the IETF. But these standards are not using the ITU work as a base, so the schism persists between what carriers want and what vendors are planning.

"The work is pretty much done on the ITU side. Unfortunately, the IETF and the ITU don't see eye to eye on this," says Yaakov Stein, chief scientist for RAD Data Communications Ltd. "Carriers want carrier-grade operation, which means a lot of strong OAM. The IETF is not doing that."

The disparity stems from carriers' and vendors' differing goals for MPLS. "The major routing manufacturers don't see this as their major thrust," Stein says. "They still see [MPLS] as IP. Cisco still sees MPLS as an accelerator for IP."

The difference is critical, because the combination of IP and MPLS will play a major role in future networks. As noted in the report Resilience, Reliability, and OAM in Converged Networks: A Heavy Reading Competitive Analysis –- published in February by Heavy Reading, Light Reading's paid research group –- carriers and equipment vendors are preparing for a network that retains multiple protocols at the edge but transports them all over an IP/MPLS core (see Survey Explodes MPLS VPN Myths and Incumbents Converge on Convergence).

What the model lacks, according to carriers, is the management tools to track down problems quickly. An MPLS network could run just fine without OAM, but it could be harder to isolate faults, leading to higher operating expenses. "Without its own OAM protocols, the MPLS cloud simply looks opaque to any attempts to locate or debug a fault," says Geoff Bennett, chief technologist at Heavy Reading and author of the report.

One alternative is to build a parallel OAM "network that runs separately to the IP 'bearer channels' and usually emerges in the POPs on a terminal server," Bennett adds. This has its obvious disadvantages: "Terminal servers cost money, and you need to run a complex, parallel network just to manage the routers."

In fact, the IETF ignored OAM on its first pass at MPLS standards, although the issue was raised. That led carriers to take their case to ITU Study Group 13, resulting in the Y.1710 and Y.1711 standards, which set the OAM requirements and define the protocols, respectively. Another recommendation, Y.1712, deals with interworking between ATM OAM and MPLS OAM.

Seeing the ITU work emerge, multiple IETF factions took a swipe at MPLS OAM, drafting proposals such as LSP-PING, a descendant of the "ping" function in IP, and LSR Self Test, for detecting network failures.

Why didn't the vendors just do what the carriers asked in the first place? Stein, who has attended OAM meetings on the ITU and IETF sides, thinks it's a matter of following the money: Carriers remain slow to spend on new networks, making carrier requirements a less urgent investment.

"Carriers are saying, 'This is what we want, but we're not going to buy anything.' So, they're not being listened to," Stein says.

It would probably be best if the ITU and IETF efforts could be combined at this point, but it's anyone's guess as to whether that will happen.

"I'm seeing the IETF try to move, and I hope the ITU tries to move, too," says Sue Hares, chief technology officer of routing-software vendor NextHop Technologies Inc. "If we continue to squabble, the ISPs won't get their solution in time."

Bennett thinks a converged effort would be good, particularly since "some really good stuff" is coming from the IETF side. "The stupid thing was for a split to happen in the first place," he says. "I think vendors really need to listen more to their customers (the carriers). And carriers need to start getting together and speaking with one (or at least fewer) voices, so that their message is loud and clear."

— Craig Matsumoto, Senior Editor, Light Reading
For more about the challenges of building IP/MPLS networks, see these Webinars:



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whyiswhy 12/5/2012 | 1:58:55 AM
re: MPLS Gets the Management Blues This sort of stuff should not be left to carriers or vendors. Their interests are at odds with each other. One wants proprietary hardware/software and the other wants commonality.

The FCC should adjudicate, and add consumer and national security protection requirements.

Prediction: Nope, ropa dope under Powell.

November. Nuff said.

-Why
VZdude 12/5/2012 | 1:58:36 AM
re: MPLS Gets the Management Blues With all the talk and action by the carriers in the METRO deployment of Ethernet it seems odd that the vendors would consider the carrier market as dormant. Layer II as well as MPLS needs OA&M features in order to reduce operational expense for carriers and ISP's. Having to dispatch out technicians to two or three possible places along a path is expensive and a poor use of your resources and time. Most vendors approach this issue from a campus point of view, which is they think you just walk over and have a look. This is not the real world of reduced head count and offices that have no human presence. In the carrier world the locations are many times miles apart even in the METRO and this leads to many windshield hours for technicians. Now that customers are making demands for an SLA contract the question is do you risk the pay back or build that into the cost a customer pays for service? Having the tools to quickly identify the source of a failure results in lowered operating cost and reduced cost to the end user.
Abby 12/5/2012 | 1:58:36 AM
re: MPLS Gets the Management Blues You highlight a valid concern. However, I think you are under estimating the IETF. As did the ITU, by not to giving them their propers. Their track record speaks for itself. The Internet did not just appear overnight, it was built on their knowledge. Therefore, they obviously are in the best position to know what to do. A dimension politicians cannot begin to imagine.
stephenpcooke 12/5/2012 | 1:58:33 AM
re: MPLS Gets the Management Blues Hi Abby,

What do you mean by 'propers' in the context of equipment providers vs. carriers? Given that the IETF is now looking at OAM functionality might that not suggest that they were wrong the first time? Were they perhaps a bit arrogant in their approach, forgetting where their bread is buttered or perhaps underestimating the resoursefulness of the carriers?

In future MPLS RFPs which standard do you think will be asked for, IETF or ITU? If your company is only designing to IETF what are your odds of making the sale? Are they better or worse than if you designed to ITU? Standing in front of a PTT or an RBOC and telling them that they don't need what they say they need is an uncommon route to success.

The article mentions that it is difficult to get carriers to speak with a common voice in standards bodies. This is true. However, if they all say something similar it is naive to ignore them. The age-old complaint of equipment providers is that they don't REALLY know what to build for each carrier (as they all have different requirements). I suggested a solution to this a while ago: let the carriers decide the standards. In sales you are often more successful if you can put yourself in your customer's shoes. If you were a carrier and asked for certain functionality in a standards body and were voted down because there are startups with the same voting power that you have, what would you do? There is always the Golden Rule (He with the Gold Rules) and carriers know this extremely well. Why not let them make the major functionality decisions so everybody (ie: equipment providers) has an even playing field (on standards at least)?
stephenpcooke 12/5/2012 | 1:58:31 AM
re: MPLS Gets the Management Blues Abby, another thing...

The IETF is obviously a bunch of techy frauds, it was Al Gore who made the Internet what it is today!!!
VZdude 12/5/2012 | 1:58:31 AM
re: MPLS Gets the Management Blues The MEF and ITU are talking about and working toward a standard way of doing OA&M. It has been my experience at the MEF that the vendors listen to the carriers and that the carriers differ very little when it comes to OA&M. They may differ on ways to deliver service and such but that is driven by what they have field deployed and ready to provision. I don't think that vendors who ask are given conflicting information but vendors that shoot in the dark looking for solutions miss the target more times than not.
zoinks! 12/5/2012 | 1:58:30 AM
re: MPLS Gets the Management Blues I think its great that operators took this upon themselves and used the ITU. The ITU understands operations much better than the IETF.

The IETFs track record on OAM has been simply to define a few MIBs and move on, with the content of the MIBs driven mostly by a propellerhead view of the world, not an operator view.

In the companies I've worked for, operator RFPs provide much better direction on real OAM needs than any IETF RFP or I-D.

Zoinks!
gbennett 12/5/2012 | 1:58:29 AM
re: MPLS Gets the Management Blues Comrades,
I have to agree with zoinks! in Post 7. There is in fact an OAM Area in the IETF. But if you take a look...

http://www.ietf.org/html.chart...

...you can see that most of the work is MIBs, RMON and "other stuff".

The fact is that OAM in a connectionless system is really hard to do, so it's not surprising that the IETF has essentially ignored it for so long. But MPLS changes all that except the IETF doesn't allow anything to be done with MPLS that can't be done with IP - hello!

I think the critical point here is not which standards body is right, but that the IETF left out OAM from the core MPLS protocols that were submitted tot he IESG a few months back.

What kind of message does this send to carriers about the suitability of MPLS as a carrier grade technology?

Cheers,
Geoff
coreghost 12/5/2012 | 1:58:25 AM
re: MPLS Gets the Management Blues I see lots of people using the word "carriers"
in this discussion, but I would advise being
careful about thinking that there is consensus
in this area among the carriers.

In some cases, we are talking about one particular
carrier, its ideas, and the ideas of the friends
of the people who work at that carrier.

What does this say about the IETF? Well, it says
that one small set of people with ideas that
not necessarily applicable to the majority of
carriers are not going to get to set the standards
for the entire industry.

Also, lurking under some of the OAM proposals,
are disagreements with the basic model for MPLS
as it came out of standards. And if you put it
to them, 95% of the carriers didn't want to see
OAM features drive the overall design of MPLS.
5% did want that, but they lost and MPLS ended
up being a whole lot more flexable.

Historically, overly complicated OAM models have
ended up being implemented by everyone and used
by no one anyway.
priam 12/5/2012 | 1:58:24 AM
re: MPLS Gets the Management Blues On the PWE3 mail list, the advocates for the pure, the good ITU model are some guys from BT. Very intelligent folks. They have a networking model whose perfection and completeness tends to be a conversation-stopper. Reminds one a little of the OSI debacle. Someone asked them, has this ever been put into practice in a real network? And they said, well no, but we don't want to keep on making the same old mistakes.

->Historically, overly complicated OAM models have
ended up being implemented by everyone and used
by no one anyway.
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