HELP! MULTILINK PPP AND MPLS

[Luis Salazar]

Hi, i really need your help in this:

i have to changed the configuration of the router, which have frame-relay to MPLS.

I have already the sentences or the commands of QoS, class map, access list, map class policy map. But I have problems with the configuration of the interface serial. I don´t know if i need to eliminate DLCI and frame-relay comands.

I have to configure the principal router to connect 3 remotes routers, for that I have 2  DM714C (2048kbps, 1024kbps). [I attached i file]

I should to type this right?:

interface Multilink2

bandwidth 3072

ip address 10.10.254.1 255.255.255.252

load-interval 30

ppp multilink

ppp multilink-group 2

but how configure the interfaces with ppp, in subinterfaces?. For the moment i have this:

interface Serial0/2/0
description Conexion REMOTE1
no ip address 10.10.254.14 255.255.255.252
   ip route-cache flow
load-interval 30
!
!
interface Serial0/1/0
no ip address
ip route-cache flow
load-interval 30
!
interface Serial0/1/0.xx point-to-point
description Conexion REMOTE2
ip address 10.10.254.10 255.255.255.252
frame-relay interface-dlci xx 
!
!
interface Serial0/1/0.51point-to-point
description Conexion REMOTE3
ip address 10.10.254.6 255.255.255.252
frame-relay interface-dlci 51
!

Where i put this:

encapsulation ppp
no cdp enable
ppp multilink
ppp multilink group 2

Please I really apreciate your comments,

Thanks a lot for help me,

LS

[Giuseppe Larosa]

Hello Luis,

subinterface on PPP intefaces and on ML PPP bundles are not supported.

But if you are moving to an MPLS L3 VPN service you don't need a "DLCI"/subinterface for each remote site you just need to peer with the PE router on central site.

It is service provider's duty to allow communication between central site and remote sites you can use static routes or eBGP session to PE router in each site.

To be noted also that ML PPP works well with links of equal speeds, if your links are 2048 kbps one and 1024 kbps the other one they are not a good match.

You can still use FR at the access link on the faster link to create  two FR subinterfaces of 1024 kbps with the SP router, and you can take advantage of three parallel links to MPLS L3 VPN service where each of them can be used to reach all the remote sites.

If this is not possible the 2Mbps should be your primary link and the 1Mbps link should be used as backup.

You could use Policy Based Routing to divert selected traffic flows over the 1 Mbps link but return traffic is not under your control.

Hope to help

Giuseppe

[Calin C.]

Hello Luis!

First of all, I don't see any "encapsulation frame-relay" under your Serial interface. Do you have a FR there?! Check this with "show frame-relay pvc" or "show frame-relay map", but I'm more than sure that your interfaces are running HDLC which is default encapsulation.

Now, depending of what you have on both ends of a point-to-point connection, you may configured your serial interfaces use PPP or Frame-Relay encapsulation and then bundle links in Multilink over PPP or Multilink over FR.

You have a functional topology there for now? I see that there is a cloud there, you need to change everything if you need PPP multilink, both on your routers and the one on the edge of the cloud (named PE in MPLS).

Anyway, we would need more details, as for now is not very clear in which step is your network. You design a new network or is already functional and you want to migrate?

Cheers,

Calin

[Luis Salazar]

It´s a functional network with FR, this is the actual config on the interfaces:

!
interface Serial0/3/0
no ip address
encapsulation frame-relay IETF
ip route-cache flow
load-interval 30
frame-relay traffic-shaping
frame-relay lmi-type cisco
!
interface Serial0/3/0.19 point-to-point
description Conexion con REMOTE1
ip address 10.10.8.2 255.255.255.248
frame-relay interface-dlci 19 CISCO  
  class enlace256
frame-relay ip rtp header-compression
!

!
interface Serial0/3/0.30 point-to-point
description Conexion con REMOTE2
ip address 10.10.1.3 255.255.255.248
frame-relay interface-dlci 30 CISCO  
  class enlace256
frame-relay ip rtp header-compression
!
interface Serial0/3/0.31 point-to-point
description conexion con REMOTE3
ip address 10.10.21.1 255.255.255.252
frame-relay interface-dlci 31 CISCO  
  class enlace320
frame-relay ip rtp header-compression
!

But i want to migrate to MPLS, installing 1 more wic1t, so i have 2 wic1t: 1 for 1024kbps and the other for 2048kbps. So I want to know how to do the configuration on the interfaces.

Thanks for answer

[Calin C. · Accepted solution]

Thanks for update, this is a more complet output. I see now that you are using FR.

What I don't understand, with all my respect, is what has to do Multilink (over PPP or FR) with MPLS.

Multilink is a method of bundling multiple interface under a logical one to achieve more throughput. You can do this with Multilink over FR in your case. You don't need PPP for multilink solution, and if you have a working FR I don't see any reason why not to use it.

Going further, MPLS is something else. Multi-Protocol Label Switching (MPLS) provides a mechanism for forwarding packets for any network protocol and it require strong knowledge to implement and use. You have there a cloud in your drawing, that cloud is under your management? Edge (cloud) routers can be configured as PE routers and the edge ones are CEs, but you still need P routers in that cloud.

Do you have a plan how you want to migrate to MPLS? Especially if this is a productive network you need to take care of downtime. And, even if I repeat myself, you need strong MPLS knowledge. I don't know your MPLS how-to level, but if you don't have an idea about what is MPLS, I strongly suggest to learn before starting to implement. Also BGP is a must for MPLS.

A good starting point:

https://www.cisco.com/en/US/tech/tk436/tk428/tsd_technology_support_protocol_home.html

So, please let us know what you have and what you want to achieve!

Cheers,

Calin