Unanswered Question
Sep 9th, 2009

i have the attached topology implemented without the new server. and i need to add the new server to the network in diffrent site, the new server uses X25/LLc/Ethernet technology and the old connection between server 1 and server 2 are Xot.

any one has any idea about the X25/LLC/Ethernet technology

are those packets are routable?

dose Cisco routers can extract the x25/llc/eth packets and switch to the right X25 destenation

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Overall Rating: 3.5 (2 ratings)
Giuseppe Larosa Wed, 09/09/2009 - 04:04

Hello Mohamed,

>> any one has any idea about the X25/LLC/Ethernet technology

are those packets are routable?

I would say no but if they are ethernet frames they can be carried by a L2 transport service like:



both can work at the vlan subinterface level.



Also DLSW+ may be a tool for this job with TCP encapsulation of LLC over ethernet frames.

to be checked if XoT can extract the X.25 from this encapsulation but if this is not possible you need to use a L2 transport service.

Hope to help


mszeftawy Wed, 09/09/2009 - 12:23

Hi Giuseppe

As this Ethernet frames will travel over MPLS network i think i should use VPLS.

But my supplier clams that this scenario will not work unless the router connected to the new server is the same router that is connected to X.25 interfaces

My question here, Dose the VPLS will help reflecting the LAN on router 1 to be as it is directly connected to router 2, reflecting the LLC encapsulation comes from the server so it can be extracted at the remote end router.

Actually I don't have enough time or available HW to test such scenario before the implementation I want to know if anyone had hands on experience in such a topology?

Giuseppe Larosa Wed, 09/09/2009 - 12:52

Hello Mohamed,

EoMPLS and VPLS are focused on transporting ethernet frames so I don't understand your supplier's claims.

Of course the L2 transport service allows to have a LAN segment that spans over both sites and this should be enough.

Hope to help


mszeftawy Sat, 09/12/2009 - 14:26

Dear All

I found a better and easer solution to be used in this topology,

I will enable the CMSN under the Ethernet interface that faces the new server, and on the same Box I will enable X.25 routing and configure x.25 routes (XOT) to route the x25 traffic over the BB.

But here I have one more question

I already have 6509 with SUP720 exist on this site and I found that it supports all the needed commands,

But this 6509 is an aggregation layer for many critical services and I want make sure that the new configuration will not impact any of them, cause I have a very old word from Cisco that the XOT is very CPU intensive,

The new configuration will contain approximately 200 X25 routes points to a different XOT -IP addresses and most probably all the sessions will be active at the same time, the used BW is not that huge, I know that the SUP-720 is very powerful but it is the 1st time to enable X.25 routing on it and add that much number of XOT routes,

Does anyone have such a practice on any similar Box??

If it is not recommended to add this configuration on the existing 6509, what new router can I get to perform the this function without problems ??


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