Re: Link Status

Hi Asif,

The reason I suggested using IP SLA is that you get one router to validate
connectivity to the other router using your backup path using inband traffic
to test rather than examining routing tables etc. Your NMS would poll the
router that is performing the IP SLA probe (the other would be set up as the
responder) to see if the connectivity is within acceptable parameters and if
not raise an alarm, triggering an event for your network operator to
investigate. Just to further explain - this is actually testing the link
between the routers and, not testing that the NMS itself can reach each of
your managed elements.

Interface state on your router could be easily determined by with snmp by
both the NMS polling and having the router generate a trap when the
interface state changes.

Points 2 and 3 appear to be within the SP network, particularly if the
attachment circuit between your router and the SP is their responsibility to
troubleshoot and rectify but may include mechanisms to assist network
connectivity verification such as BFD, 802.1ah, 802.3ag and Y.1731

If you want something to perform a root cause analysis for you which will be
NMS dependant - the specific product, the modules and possibly the business
rule customisation may have impacts on this.

Cheers,
Adam

On Sun, Aug 22, 2010 at 5:16 PM, Asif Vanoo <asif_at_vanoo.net> wrote:

> Hi,
>
> In MPLS network there are couple of reachability failure options.
>
> - Interface of my router goes down
> - next hop not reachable- MPLS Provider
> - Somewhere in between on MPLS cloud
>
> What if Interface of my router facing SP is up and reachable but cannot
> reach my other end. Problem could be in SP or problem could be my other
> end.
> How would NMS behave in this situation?
>
> Thanks
> Asif
>
> On 8/22/2010 4:37 AM, Adam Booth wrote:
>
> Hi Asif,
>
> There's more than one way to do it but one method I would consider
> suggesting is to look at IP SLA ICMP tests between the interfaces of you
> routers that are facing the SP MPLS network and your NMS uses the RTTMON
> SNMP MIB to verify connectivity.
>
> This is the guide on CCO about IP SLA ICMP echo operations
> http://www.cisco.com/en/US/docs/ios/12_4/ip_sla/configuration/guide/hsicmp.html
> This should be the MIB of interest
> http://tools.cisco.com/Support/SNMP/do/BrowseMIB.do?local=en&mibName=CISCO-RTTMON-MIBfor your NMS to query
>
> Cheers,
> Adam
>
>
> On Sun, Aug 22, 2010 at 5:53 AM, Asif Vanoo <asif_at_vanoo.net> wrote:
>
>> Hi GS,
>>
>> Got a Question,I got this scenario
>>
>> Loc_A connects to Loc_B with P-2-P 10Mb link as primary and MPLS link as
>> backup link.
>> NMS is located at Loc_A which monitors both links ( P-2-P & MPLS ) and on
>> both location Routers.
>> OSPF is the routing protocol
>> MPLS is via a Service provider
>>
>> How can I identify my MPLS link is up and reachable till Loc_B when P-2-P
>> link is up??
>>
>> Thanks
>> Asif
>>
>>
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Received on Sun Aug 22 2010 - 17:49:07 ART