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jamesbond
jamesbond
12/4/2012 | 10:35:24 PM
re: Alcatel Unveils New Routing Technology
Giles,

thanks for the answers - and yes now I see your
point. About MPLS FRR - do you think
this is practical/scalable, i.e. having a backup path for each lsp (i know backup lsp's can be shared at the cost of bandwidth guarantee) between each hop? Does it handle multiple failures?

just trying to learn.
fiber_r_us
fiber_r_us
12/4/2012 | 10:35:23 PM
re: Alcatel Unveils New Routing Technology
Giles,

Do you think 50ms is a hard requirement? Or do you think customers have simply been told that it is a requirement (and believed it) or that it just sounds cool? Is there any major application on a DATA network that requires 50ms (i.e. the applications ceases to work)?
euler
euler
12/4/2012 | 10:35:23 PM
re: Alcatel Unveils New Routing Technology
lock-step processor mirroring is an option only when the software can't be modified (which doesn't apply in this case). you make the stuff resilient by event-based logging of relevant state to either the redundant card's DRAM or some highly-available shared persistent backing store.
bitnews
bitnews
12/4/2012 | 10:35:22 PM
re: Alcatel Unveils New Routing Technology
There are multiple implementation of FRR and each of them have there own issues, fell free to go read on cisco / junipers website about there implementations. One of the problems arises from if you keep a per interface label space or a per router label space. Anyways its a bit off topic so I will drop but in my idea yes its pratical and yes its scalable (depending on the implementation).
fiber_r_us
fiber_r_us
12/4/2012 | 10:35:19 PM
re: Alcatel Unveils New Routing Technology
bitnews said:
>There are multiple implementation of FRR...
>...but in my idea yes its pratical and yes its
>scalable (depending on the implementation).

But, is it required?
Skiier_Dude
Skiier_Dude
12/4/2012 | 10:35:17 PM
re: Alcatel Unveils New Routing Technology
There are many applications which require rapid fail over of redundant links. Have done some work in the Process Control world. While many of these systems in the past have used old or proprietary protocols (Modbus +), many are moving to IP networks given the lower cost of the hardware. Some will encapsulate these older protocols in IP, others will will make wholesale changes.

Long story short, that in these environments if the rapid fail of a redundant link is not possible, process control hosts will take action to shut down automated operations (or won't) and in either case can often be costly for the user.

By way of example, mining operation monitors PLCs using an IP network over fiber. Company moves 30K Tons of Ore per hour on a conveyor system. Disaster strikes, conveyor breaks, primary fiber path is also broken. IP network takes 4 seconds to reroute and notify controller of disaster. In the meanwhile, 32 Tons of ore have piled up on the ground. Reroute the traffic in 50ms, and the IT guy has a smaller mess to clean :-)
dhanush
dhanush
12/4/2012 | 10:35:16 PM
re: Alcatel Unveils New Routing Technology

thus spaketh fiber_r_us:
FRR
But, is it required ?

-------------------------

Exactly !

Why not just Edge to Edge protection switching ?
Wouldn't that take some complexity away ??

For that matter why not good old IP restoration ?
Can't something be done about reducing IP restoration time ?? We have afterall now vendors that boast of 50ms rapid spanning tree protection for ethernet.

Do enterprises take their SPs to court for failing to provide them 50ms protection ? or even 50second protection ?

How different is five 9s reliability from four 9s reliability or three 9s reliability ?

On a related note, was 50 ms SONET protection a design objective or a byproduct ? a byproduct of simplicity for instance !!

regards
-dhanush-















fiber_r_us
fiber_r_us
12/4/2012 | 10:35:16 PM
re: Alcatel Unveils New Routing Technology
First, 50ms has nothing to do with 5-nines. If all you needed to do was make 5-nines on an annual basis (that's 5 minutes and 15 seconds), your network could converge quite nicely many times with multi-second failovers.

50ms originated from some guy at Bell labs deciding that was the maximum time that could elapse before an outage was detectable by the human ear (if you were really trying to listen for it). Sort of the same reason refresh rates on CRTs are around 70Hz (so your eye can't detect the refresh). The 50ms was later incorporated into the SONET standard, and now has achieved an unbelievable level of religious following for no apparent reason (other than thats what we have all been taught and it sounds really cool).
fiber_r_us
fiber_r_us
12/4/2012 | 10:35:16 PM
re: Alcatel Unveils New Routing Technology
Yep... got lots of that mining data traffic running over those carrier backbones... I really should design my whole network around that application :-)

In the case you mention where the real-time process control world is migrating to Ethernet (because of "the lower cost of the hardware"), how are they going to get fast enough recovery times in thier LAN networks?
bitdropper
bitdropper
12/4/2012 | 10:35:14 PM
re: Alcatel Unveils New Routing Technology
"The 50ms was later incorporated into the SONET standard, and now has achieved an unbelievable level of religious following for no apparent reason (other than thats what we have all been taught and it sounds really cool)."

--------------------------------------------------

For better or worse, whether any of us likes it or not, 50ms *is* part of the SONET standard. As such, it has become an "accepted" [yes I know it's subjective] recovery interval. All that means, is the legacy networks are built based upon it; and until something better comes along to displace it, 50ms will remain the benchmark by which carriers [customers] compare alternatives. The argument of its suitability is moot. This is why any *better* way has to be able to do it in 50ms, every time, perfectly; and that's only to be considered *equal* in "quality"! Otherwise, there's no point in switching from what you've got.
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