[c-nsp] Multilink PPP Was -> Re: Balancing T1's with CEF

[Everton Diniz]

CJ,

I don´t know if happens on 7500, but on 7200 if you config MLPPP using
links connected in different slots, even same PA, occurs problems like
stop traffic without reason or the MLPPP is down.

On Thu, Jul 30, 2009 at 12:15 PM, Security Team<cisco at peakpeak.com> wrote:
> Well.....we arent' doing per packet and the destinations are definitely
> different.
>
> The last time this problem occurred I did a clear ip cache and it went away.
> Since it isn't doing it this time I guess I thought I should try something
> else.
>
> Here is what I tried, I tried converting to multilink ppp encaps instead of
> HDLC to see if that would have any effect, and it didn't.
>
> (on both ends):
>
> aaa new-model
> aaa authorization network noauth none
> aaa session-id common
>
> interface Multilink1
>  no ip address
>  load-interval 30
>  no cdp enable
>  ppp authorization noauth
>  ppp multilink
>  ppp multilink group 1
>  no shut
> !
> Interface Serial1/1/0
>  encapsulation ppp
>  ppp authorization noauth
>  shut
>  no shut
> !
> Interface Serial1/1/3
>  encapsulation ppp
>  ppp authorization noauth
>  shut
>  no shut
> !
> Interface Serial1/0/0/12:0
>  encapsulation ppp
>  ppp authorization noauth
>  shut
>  no shut
>
> So with 3 static routes like this:
>
> ip route x.y.z.0 255.255.255.0 serial1/1/0
> ip route x.y.z.0 255.255.255.0 serial1/1/3
> ip route x.y.z.0 255.255.255.0 serial1/0/0/12:0
>
> The customer works but still has the problem where all the traffic sacks one
> line inbound to their 28xx from our 7507.  So all we accomplished here
> really was pre-build a multilink PPP bundle but just change the encaps for
> each serial interface to PPP instead of HDLC.
>
> Then I thought what I'd do is add each serial interface to the multilink
> bundle using:
>
> Int Serial1/1/0
>   ppp multilink
>   ppp multilink group 1
> Int Serial1/1/3
>   ppp multilink
>   ppp multilink group 1
> Int Serial1/0/0/12:0
>   ppp multilink
>   ppp multilink group 1
>
> That is when the fun stopped (no packets routed at all). I did get this
> message on the console:
>
> Jul 30 09:03:09 MDT: %RP_MLP-5-LINKTYPEMISMATCH: Link(Serial1/0/0/12:0)
> added, Bundle(Multilink1) may not be distributed
>
> Not sure what this means.
>
> So I assume what I should have done in addition to adding the ppp multilink
> grouping to the serial interfaces is remove the static routes and replace
> them with this instead right?
>
> ip route x.y.z.0 255.255.255.0 Multilink1
>
> I haven't ever configured multilink PPP before but this is right isn't it?
>
> Thanks,
> CJ
>
>
> On 7/30/09 7:32 AM, "Matthew Huff" <mhuff at ox.com> wrote:
>
>> Unless you do "per-packet" load-sharing (which you don't want to do since
>> it's cpu switched), the path is session based. If most of the traffic is
>> going from one source to one destination, it won't be load-shared. What do
>> the routing tables look like in both directions?
>>
>> ----
>> Matthew Huff       | One Manhattanville Rd
>> OTA Management LLC | Purchase, NY 10577
>> http://www.ox.com  | Phone: 914-460-4039
>> aim: matthewbhuff  | Fax:   914-460-4139
>>
>>
>>> -----Original Message-----
>>> From: cisco-nsp-bounces at puck.nether.net [mailto:cisco-nsp-
>>> bounces at puck.nether.net] On Behalf Of Security Team
>>> Sent: Wednesday, July 29, 2009 11:24 PM
>>> To: cisco-nsp at puck.nether.net
>>> Subject: [c-nsp] Balancing T1's with CEF
>>>
>>> I rebooted a 7507 router that had a site connected with 3 T1's and now
>>> all
>>> the traffic is nailing one line instead of being distributed over all 3
>>> using the static routes/CEF.
>>>
>>> I did look at the Cisco troubleshooting tips but didn't see anything
>>> immensely helpful.  Here is a config snippet on the 7507 side (it's
>>> obviously nothing
>>> whizzy).
>>>
>>> Has anyone seen this before?  I did an ip clear cache and also tried
>>> doing a
>>> shut/no shut on each line individually on the 7507, but the traffic to
>>> the
>>> customer's
>>> 28xx router always sacks one line.  It seems like in the past I did
>>> some
>>> kind of clear on the 7507 and things got better, but I can't recall
>>> what
>>> that may have been.
>>>
>>> Thanks,
>>> CJ
>>>
>>> 7507 (all PA adapters on the same VIP) config. One T1 comes in on a
>>> chan DS3
>>> card breaking out individual T1¹s, and the other 2 T1¹s come in on a 4-
>>> port
>>> PA adapter T1 card. I¹m not using dCEF since I have never had good luck
>>> with
>>> it.
>>>
>>> ip cef
>>> !
>>> interface Serial1/0/0/12:0
>>>  bandwidth 1536
>>>  ip address x.x.x.x y.y.y.y
>>>  load-interval 30
>>>  no fair-queue
>>>  down-when-looped
>>>  no cdp enable
>>> !
>>> interface Serial1/1/0
>>>  bandwidth 1536
>>>  ip address x.x.x.x y.y.y.y
>>>  load-interval 30
>>>  no fair-queue
>>>  down-when-looped
>>>  no cdp enable
>>> !
>>> interface Serial1/1/3
>>>  bandwidth 1536
>>>  ip address x.x.x.x y.y.y.y
>>>  load-interval 30
>>>  no fair-queue
>>>  down-when-looped
>>>  no cdp enable
>>>
>>> _______________________________________________
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>
>
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