Saturday, 8 August 2009

IP Backbone Fast Re-Route Capability: Is this feature present on most carriers' MPLS VPN service?

IP Backbone Fast Re-Route Capability: Is this feature present on most carriers' MPLS VPN service?

As far as I know most major vendors should have FRR implemented. I am sure Cisco and Juniper both does.

Multiprotocol Label Switching (MPLS) Fast Reroute (FRR) refers to local protection methods such as one-to-one and many-to-one (facility) backup. In the general, the term FRR has become a shorthand way of describing the entire spectrum of MPLS traffic protection mechanisms.

In general MPLS traffic protection for Resource Reservation Protocol (RSVP)-signaled label-switched path (LSP) failures is provided by several complementary mechanisms. These protection mechanisms include local protection (fast reroute, link protection, and node-link protection), and path protection (primary and secondary paths). Local protection in conjunction with path protection can provide minimum packet loss for an LSP, and control the way the LSP is rerouted after a failure.

Traditionally, both types of protection rely on fast detection of connectivity failure at the physical level. TE is usually enabled in the core network, where the capacity of the links is high. If a link or a router fails, traffic is rerouted around the failure. This rerouting happens for IP and for MPLS traffic relatively fast. However, even if the rerouting takes only a few seconds, it might mean that a lot of traffic is dropped to the point of failure because of the high capacity of the links. For certain traffic, such as Voice over IP (VoIP), this can be devastating for the service. Although links can potentially be protected at Layer 1—for example, with a mechanism called automatic protection switching (APS)—having a protection at the level of MPLS is best. APS is a well-known mechanism for protecting optical links. A disadvantage of APS is that for every protected link, a backup link and a card on either side are waiting idle until they are needed and the failing protected optical link is switched over to this backup link.

Link and node protection with TE is more efficient because an idle backup link for every protected link is not needed. Therefore, link and node protection used with TE is cheaper than an optical protection scheme. A backup tunnel for each protected link or node is created in advance. That means no time is wasted by having to signal the backup tunnel when the protected device fails. This time can be quite long because a path must be computed for the backup tunnel, and then it must be signaled. The following two explain the local protection schemes possible with TE: link protection and node protection. The two schemes have one thing in common: The repair is done as close to the point of failure as possible. Both methods provide local repair. As such, they are pretty fast and reroute the LSPs from the protected link onto the backup tunnel in tens of milliseconds. A number you might hear a lot is the 50-msec one. That is because this number is also referred to a lot when talking of the switchover time of SONET links. Link and node protection with MPLS TE is referred to as FRR.





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santanu said...

Hi Fiza,

Many thanks for your kind comments. I have not been able to keep up the blogs very efficiently of late due to my personal work load for awhile. But am trying to get back into doing it regularly again.:-)
Please let me know if there is any subject in particular that you will like to see discussed and I shall definitely try my best to include that, i.e., if I am able to fathom the subject:-)

Thanks a lot!

Best Regards


Breakfast At Serengeti

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The Ngorongoro Family

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Click on the Picture Above To Make It Larger

Tabloid Time: The Aliens Are a'Landing ?!.. ;-)

At the risk of being ridiculed and being labelled a freak, I shall like to draw everyone's attention to the following recent events....If you watch the videos then turn on the sound for the commentary...

Fireball across Ausin, Texas (16th Feb 2009). According to BBC, apparently, its NOT debris from a recent satellite collision...:

Same in Idaho in recent times. NO meteor remains found yet:

Exactly same in Sweden:

This was recorded on 25th Feb 2007 in Dakota, US:

This year has seen three of the spookiest UFO videos surface, with people in India, Mexico and even in space, NASA, spotting things they couldn't explain:

CHECK out this one on 24th Januray, 2009 in Argentina close to Buenos Aires:
You tube:
Press Coverage

AND Lastly, and more importantly, from Buzz Aldrin on Apollo 11 :

Heh?! Don't know how authentic these news are... don't even know if these are UFO's or meteors or ball lightning or something else. But, if meteors, then where are the meteorites ? However, I see no reason why life cannot exist in other planets and why they could not be sneaking around here :-) . I for one, have long suspected some of my relations to be space aliens or at least X-people from X-files :-)

I am waiting for a job on an Alien spaceship myself. :-)

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