[c-nsp] Multilink PPP over Frame and ATM

Cory Ayers cayers at ena.com
Tue Feb 14 11:20:37 EST 2006


I tried to do the same thing a year ago.  We had previously balanced up
to six T1s with per-packet load-sharing.  After upgrading to a 7606 we
lost this functionality.  MLPoATM and MLPoFR are only for fragmentation
and interleaving (QOS).  As long as you are using a 7200 and 2600, just
enable load-sharing on each interface and be done with it.

Interface ATMX/Y.1
 ip load-sharing per-packet

Any equal path routing protocol (including static) will provide both
forwarding paths.  Packets will either be CEF switched or process
switched (if CEF is disabled).

Your other option would be to have the provider hand you a 3M ATM
circuit.  I've heard this referred to as multipoint-to-point, but I've
never done it.

Cory

> Hi all,
> 
> This one's kind of stumping me...  We're a Covad partner, and
> sometimes it's most economical for everyone involved to go with a
> Covad T1 for some customers.  Covad buys a T1 loop from Verizon and
> puts a standard T1 router on the CPE side and they talk frame relay
> out the T1.  The rest of Covad's DSL network is ATM, so they do a
> Frame <-> ATM conversion.  Our backhauls to Covad are ATM T3s.
> 
> So in this era of ever-increasing bandwidth use, we've got people
> wanting more than 1.5 Mb/s of symmetric bandwidth.  For straight T1s,
> there's plenty of options.  For these Covad T1s, I wasn't seeing a
> good way to truly "bond" the T1s.   Then I saw that Speakeasy was
> doing a big promotion on Covad T1s and they were speaking of
> "bonding".  I found this document on their site:
> http://www.speakeasy.net/pdf/Speakeasy_BondedT1_WhitePaper.pdf
> On the bottom of page 6, they talk about Mulitlink PPP over Frame and
ATM.
> 
> So that looked like the answer.  I've got two Covad T1s on order into
> the office.  One is done, the next should be ready Monday.  I've got a
> 2620 with two T1 wics in it.  The other end is the trusty 7206.
> 
> I used the two following docs to setup both ends.
> 
> frame:
>
http://www.cisco.com/univercd/cc/td/doc/product/software/ios124/124cg/hq
os
> _c
> /part30/ch05/qslfifr.htm#
> 
> atm:
>
http://www.cisco.com/univercd/cc/td/doc/product/software/ios122/122newft
/1
> 22
> t/122t13/ftatmmlt.htm
> 
> Here's where I'm confused.  I have this up and running with the single
> T1 and it seems to work.  But in both of those docs they talk about
> this multilink setup being strictly for QoS.  This overview doc
> (http://www.cisco.com/warp/public/788/voice-qos/designing-mlp-over-fr-
> atm.html)
> even states that you cannot use this to bond two circuits together.
> So how is it "multilink" then?  I understand that I'm layering PPP
> over everything to get control of fragmentation and QoS away from the
> underlying transport, but it seems like a misnomer.
> 
> And of course Speakeasy claims to be doing it with Cisco 18xx CPE and
> Juniper aggregation routers and that confuses things even further.
> 
> Am I wasting my time trying to do this?  The docs are real fuzzy on
> the part I'm interested in.  QoS is not even a concern for these
> customers.
> 
> Anyone doing anything remotely like this?  Any ideas?  I'll know if it
> works sometime next week, but I'm really wanting to understand the
> concepts here...
> 
> Thanks,
> 
> Charles
> 
> Here's a snippet of both ends of the config.
> 
> CPE:
> !
> interface Serial0/0
>  description covad circ 103-341-xxx vz circ 32HCFU.239xxx hse 396
>  no ip address
>  encapsulation frame-relay IETF
>  no fair-queue
>  frame-relay lmi-type ansi
> !
> interface Serial0/0.1 point-to-point
>  description frame pvc
>  frame-relay interface-dlci 16 ppp Virtual-Template1
> !
> interface Serial0/1
>  description covad circ 103-336-xxx vz circ 32HCFU.227xxx hse 386
>  no ip address
>  encapsulation frame-relay IETF
>  no fair-queue
>  frame-relay lmi-type ansi
> !
> interface Serial0/1.1 point-to-point
>  description frame pvc
>  frame-relay interface-dlci 16 ppp Virtual-Template1
> !
> interface Virtual-Template1
>  description ppp template for MPoFR
>  bandwidth 3072
>  ip address 10.1.1.2 255.255.255.252
>  ppp multilink
>  ppp multilink interleave
> !
> 
> 7206:
> !
> interface ATM4/0.2614 point-to-point
>  pvc 0/2614
>   encapsulation aal5snap
>   protocol ppp Virtual-Template1
>  !
> !
> interface ATM4/0.2615 point-to-point
>  ip unnumbered Loopback8
>  pvc 0/2615
>   encapsulation aal5snap
>  !
> !
> interface Virtual-Template1
>  description test MPoATM office circ
>  bandwidth 3072
>  ip address 10.1.1.1 255.255.255.252
>  ppp multilink
>  ppp multilink interleave
> !
> mppp-test-568#ping 10.1.1.1
> 
> Type escape sequence to abort.
> Sending 5, 100-byte ICMP Echos to 10.1.1.1, timeout is 2 seconds:
> !!!!!
> Success rate is 100 percent (5/5), round-trip min/avg/max = 12/15/16
ms
> mppp-test-568#
> 
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