ppp multilink

[dathaide]

hi

I have seen users use the int virtual template command and also the ppp multilink command (and sometimes both) to combined sync interfaces. What is the the difference. Can't one use only the multlink command and assign it to the serial interfaces

thanks

[mark.weaver]

I used the virtual template and multilink to aggregate 4x1mb links. The virtual template is used to assign the ip address to (via a loopback interface if you like)this is similar to using a dialer interface with isdn.

[dathaide]

Thanks for the reply but won't this configuration work on syn interfaces as well

interface Multilink1

ip address 1.1.1.1 255.255.255.0

ip tcp header-compression iphc-format

ppp multilink

ppp multilink group 1

ip rtp header-compression iphc-format

ip rtp priority 16384 16383 192

interface Serial1/0:0

no ip address

encapsulation ppp

ppp multilink

ppp multilink group 1

!

interface Serial1/1:0

no ip address

encapsulation ppp

ppp multilink

ppp multilink group 1

hence why the need for a virtual template

[dathaide]

Thanks for the reply but won't this configuration work on syn interfaces as well

interface Multilink1

ip address 1.1.1.1 255.255.255.0

ip tcp header-compression iphc-format

ppp multilink

ppp multilink group 1

ip rtp header-compression iphc-format

ip rtp priority 16384 16383 192

interface Serial1/0:0

no ip address

encapsulation ppp

ppp multilink

ppp multilink group 1

!

interface Serial1/1:0

no ip address

encapsulation ppp

ppp multilink

ppp multilink group 1

hence why the need for a virtual template

[thisisshanky]

Both configurations are valid. Multilink can be enabled with the configuration you posted, or with Virtual templates. Some of my thoughts:

1. A virtual template interface clones a virtual access interface and the configuration from the template is inherited by the cloned interface. This configuration will then be applied to the serial or ISDN bri interface participating in multilink. I think the obvious advantage of this is that, when there is no longer a requirement for the Virtual access interface (say link goes down). So virtual templates are useful in an aggregation router doing multilink in large scale.

2. The configuration that you posted lets you create multiple multilink interfaces, and group physical interfaces into separate groups. I dont think you can do the same with a Virtual template configuration, because you do not specify the virtual template number under each physical interface.