[j-nsp] optimized switchover
Nilesh Khambal
nkhambal at juniper.net
Tue Sep 8 05:19:38 EDT 2009
Hi Matthias,
I am no expert on J-Seris, but looking at BFD state, I feel that there is an
issue sending or receiving BFD packets on your Router B. AdminDown state
here may mean that no packets were ever received from Router A. If you are
running a Junos Enhanced Services version on these J-Series routers, can you
check if any specific policy needs to be created to allow these BFD packets
(UDP/3784)? Also, check if any firewall filters blocking BFD packets. Try to
run tcpdump on both routers to see if BFD packets are being received or not.
Thanks,
Nilesh.
On 9/8/09 1:40 AM, "Matthias Gelbhardt" <matthias at commy.de> wrote:
> Hi!
>
> No, actually they are directly connected, so I do not know, why there is
> a multihop output. Perhaps somehow he thinks to be not directly
> connected and that is the problem?
>
> Both routers are J6350.
>
> Regards,
>
> Matthias
>
> Nilesh Khambal schrieb:
>> Hi Matthias,
>>
>> Are these peers established over a directly connected IPs or is this an
>> indirect session?
>>
>> The session shows multihop on both routers from the show output provided
>> below.
>>
>> What is the router platform on both sides?
>>
>> Thanks,
>> Nilesh
>>
>>
>> On 9/8/09 1:25 AM, "Matthias Gelbhardt" <matthias at commy.de> wrote:
>>
>>> Hi!
>>>
>>> That is the doc I have used for configuring.
>>>
>>> Both routers are Juniper routers over a Laver 2 Link directly connected.
>>> One router is 9.3R2.8 The other 9.4R2.9.
>>>
>>> Regards,
>>>
>>> Matthias
>>>
>>> Nilesh Khambal schrieb:
>>>> Hi Matthias,
>>>>
>>>> What JUNOS version are you running on this router? Is other end router also
>>>> a Juniper router? Are both peers directly connected or is this a multihop
>>>> session?
>>>>
>>>> Try this doc link see if it can help.
>>>>
>>>>
http://www.juniper.net/techpubs/software/junos/junos85/swconfig85-routing/i>>>>
d
>>>> -13279139.html#id-13279139
>>>>
>>>> Thanks,
>>>> Nilesh.
>>>>
>>>>
>>>>
>>>> On 9/8/09 12:53 AM, "Matthias Gelbhardt" <matthias at commy.de> wrote:
>>>>
>>>>> Has no one an idea? It seems, that I am really stuck here. Do I have to
>>>>> activate something on the other side (hence the AdminDown status?)
>>>>>
>>>>> Regards,
>>>>>
>>>>> Matthias
>>>>>
>>>>> Matthias Gelbhardt schrieb:
>>>>>> Hello David,
>>>>>>
>>>>>> great tip. Unfortunatly BFD for BGP - though detailed documented - has
>>>>>> no examples flying around. Perhaps I am missing something here.
>>>>>>
>>>>>> I have two routers connected via iBGP. I have tried to make the
>>>>>> configuration rather simple (only the important parts, BGP session is up
>>>>>> and running):
>>>>>>
>>>>>> This is the same on both sides (change in the IP-addresses of course)
>>>>>>
>>>>>> protocols bgp {
>>>>>> group internal {
>>>>>> type internal;
>>>>>> neighbor 91.190.xxx.xxx {
>>>>>> local-address 91.190.xxx.xxx;
>>>>>> bfd-liveness-detection {
>>>>>> minimum-interval 1000;
>>>>>> multiplier 3;
>>>>>> }
>>>>>> }
>>>>>> }
>>>>>>
>>>>>> Router A:
>>>>>> show bfd session extensive
>>>>>> Detect Transmit
>>>>>> Address State Interface Time Interval
>>>>>> Multiplier
>>>>>> 91.190.xxx.xxx Init 3.000 1.000 3
>>>>>> Client BGP, TX interval 1.000, RX interval 1.000
>>>>>> Session down time 00:00:04
>>>>>> Local diagnostic CtlExpire, remote diagnostic None
>>>>>> Remote state Down, version 1
>>>>>> Min async interval 1.000, min slow interval 1.000
>>>>>> Adaptive async TX interval 1.000, RX interval 1.000
>>>>>> Local min TX interval 1.000, minimum RX interval 1.000, multiplier 3
>>>>>> Remote min TX interval 1.000, min RX interval 1.000, multiplier 3
>>>>>> Local discriminator 1, remote discriminator 1
>>>>>> Echo mode disabled/inactive, no-absorb, no-refresh, update-adj
>>>>>> Multi-hop, min-recv-TTL 0, route table 0, local-address 91.190.xxx.xxx
>>>>>>
>>>>>> 1 sessions, 1 clients
>>>>>> Cumulative transmit rate 1.0 pps, cumulative receive rate 1.0 pps
>>>>>>
>>>>>> Router B:
>>>>>> show bfd session extensive
>>>>>> Detect Transmit
>>>>>> Address State Interface Time Interval
>>>>>> Multiplier
>>>>>> 91.190.xxx.xxx Down 0.000 1.000 3
>>>>>> Client BGP, TX interval 1.000, RX interval 1.000
>>>>>> Local diagnostic None, remote diagnostic None
>>>>>> Remote state AdminDown, version 1
>>>>>> Min async interval 1.000, min slow interval 1.000
>>>>>> Adaptive async TX interval 1.000, RX interval 1.000
>>>>>> Local min TX interval 1.000, minimum RX interval 1.000, multiplier 3
>>>>>> Remote min TX interval 0.000, min RX interval 0.000, multiplier 0
>>>>>> Local discriminator 1, remote discriminator 0
>>>>>> Echo mode disabled/inactive, no-absorb, no-refresh
>>>>>> Multi-hop route table 0, local-address 91.190.xxx.xxx
>>>>>>
>>>>>> 1 sessions, 1 clients
>>>>>> Cumulative transmit rate 1.0 pps, cumulative receive rate 0.0 pps
>>>>>>
>>>>>> I see the diagnostic on router A but do not understand it. I thought the
>>>>>> minimum-interval might be too low, so I set it up to a thousand.
>>>>>>
>>>>>> Regards,
>>>>>>
>>>>>> Matthias
>>>>>>
>>>>>>
>>>>>> David Ball schrieb:
>>>>>>> There are likely several answers to that, all dependant on your
>>>>>>> topology and protocol use. But, a good place to start would be BFD
>>>>>>> (bidirectional forwarding detection). Juniper has decent support for
>>>>>>> it working with other protocols (OSPF, ISIS, BGP, RIP), notifying them
>>>>>>> that something may be wrong, allowing them to then make a decision
>>>>>>> (support may differ from protocol to protocol). That may be a good
>>>>>>> start point.
>>>>>>>
>>>>>>> http://www.juniper.net/techpubs/software/junos/junos95/swconfig-routing/
>>>>>>> sw
>>>>>>> co
>>>>>>> nfig-routing-IX.html#B
>>>>>>>
>>>>>>>
>>>>>>> David B
>>>>>>>
>>>>>>>
>>>>>>> 2009/9/6 Matthias Gelbhardt <matthias at commy.de>:
>>>>>>>> Hi!
>>>>>>>>
>>>>>>>> I wonder what the best practices for optimized switchovers would be?
>>>>>>>> I mean
>>>>>>>> fast comprehension of failed BGP connections? A fibre cut or
>>>>>>>> something like
>>>>>>>> that, how can I be sure, that my routers are detecting the failed
>>>>>>>> session as
>>>>>>>> soon as possible? What would be the best practices fpr that?
>>>>>>>>
>>>>>>>> Regards,
>>>>>>>>
>>>>>>>> Matthias
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