ADSL question for MER !!!

[Francis Garcia]

Hi folks,

I got a question for you guys because I'm a little confused about a term that I've never used before.

I got a c1760 router with 2 ADSL wics. One of my services providers is using PPPoA in their networks and all is fine with the static IP address that I have with them, but, the other services provider is using a protocol called MER (Mac Address Encapsulation) that I don't know what is the equivalent for cisco. The real problem is that I cannot use my static ip address using PPPoA with that services provider, the only way to use my static IP address is using MER or using bridging from the ATM interface to my 1760's lan interface, and as you know I just have an FastEthernet interface in that router. I want to use my router as CPE, not the modem that they sent me.

Resuming - What is the equivalent of MER for Cisco? And If u have some samples of how to configure it, plz let me know.

Regards,

Francis

[marikakis]

My guess is that MER refers to "RFC1483 with MAC Encapsulated Routing" and the cisco equivalent would be "RFC1483 Routing". Guidelines for configuring this can be found at:

http://www.cisco.com/en/US/tech/tk175/tk15/technologies_configuration_example09186a008071a8a0.shtml#backinfo

[Rolitto]

Agreed!

[Ronit Bhattacharjee]

Hi Francis,

Here's a sample configuration for MER (also known as enet encapsulation by some modems)

interface ATM0
 no ip address
 no ip redirects
 no ip unreachables
 no ip proxy-arp
 ip route-cache flow
 no atm ilmi-keepalive
 dsl operating-mode auto
!
interface ATM0.1 point-to-point
 description $ES_WAN$$FW_OUTSIDE$
 ip address dhcp client-id FastEthernet0 hostname router
 ip virtual-reassembly
 atm route-bridged ip
 pvc 8/35
  encapsulation aal5snap

Feel free to change the pvc according to your PVC. Basically, we need to provide a mac-address for the pppoe sessions, that's why we use "ip address dhcp client-id FastEthernet0 hostname router" which would use the mac address of your fastethernet 0 (or any other) interface's mac address.

[paolo bevilacqua]

we need to provide a mac-address for the pppoe sessions, that's why we use "ip address dhcp client-id FastEthernet0 hostname router

There is no pppoe in the example given. The command
ip address dhcp

is needed to get an IP address, in in most cases no options are necessary.

[Ronit Bhattacharjee]

I correct myself. the "ip address dhcp client-id FastEthernet0 hostname router" adds a source mac address to every outgoing packet. Still, this is the configuration for MER

[paolo bevilacqua]

the "ip address dhcp client-id FastEthernet0 hostname router" adds a source mac address to every outgoing packet.

That is not correct either. An ethernet header is added to each packet because the command "atm route-bridged".

As mentioned before, what "ip address dhcp" does, is to dynamically reques an address, nothing else.

[marikakis]

Thanks guys for cleaning up. My greetings and ratings.

[JM33]

Thank you for the config and its works.  Was able to get an ip from the provider but the NAT does not work.  Do i need a dialer interface to make it work?

[marikakis]

Hi Francis,

Ronit seems to know better, while I was just guessing. Sorry if I caused you confusion.

Kind regards,

Maria

[Ronit Bhattacharjee]

Hi Maria,

The link you referred to is correct, but is simple ADSL without any encapsulation.

Hope this helps

[Francis Garcia]

Thank u guys,

I got a lil cuestion for you, don't I need to use any virtual interface like a Dialer or VBI to acomplish the configuation?.

Regards,

Francis

[Ronit Bhattacharjee]

Hi Francis,

You need dialer in case you have a PPPoA or a PPPoEoA link and you need to negotiate parameters like authentication etc. You don;t need a dialer in case you have a direct DSL line.

[marikakis]

Hi Ronit,

Nothing works without the correct encapsulation, so thanks for saying "correct, but ..." instead of "wrong"! :-)

By the way, in my opinion, "simple ADSL without any encapsulation" doesn't exist. DSL setups have so many different encapsulations on top of the DSL physical layer, and with one encapsulation being on top of the other, that I always have to look them up, although I used to write code for such stuff.

Kind Regards,

Maria