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DSPU over 2 DLSW router on same ethernet

Can I use DSPU over two router connected on the same ethernet segment that through two wan links connects with a central site. Both router have a DLSW peer active with the central site and a backup peer configured to another router at the central site. Do I have any loop problem with this? do I have to configure etherneth redundancy to avoid it? Is DSPU compatible with ethernet redundancy?

thanks in advance

5 REPLIES
Silver

Re: DSPU over 2 DLSW router on same ethernet

I do not see a loop. However, I am not 100% sure without additional information. Please provide the router configurations and answer the following questions:

1. I assume that you use ethernet interface on both routers for DSPU and use a VDLC for the upstream host link. Is this correct? I can verify this with the router configuration

2. Do you change the MAC address of the ethernet interface? (i.e. interface command mac-address)

3. Do the DSPU routers on a hub or a switch?

New Member

Re: DSPU over 2 DLSW router on same ethernet

I have not configurations yet, anyway just to answer to your questions:

1-yes

2-no

3-switch

Silver

Re: DSPU over 2 DLSW router on same ethernet

I do not fully understand the topology. Let me rephrase it.

You will use the MAC address of ethernet interface of router 1 (MAC1) and 2 (MAC2) for the downstream PUs. In other words, some of the downstream PUs will point to MAC1; while some of the downstream will point to MAC2. As there is no linkage between DSPU (for downstream PUs) and DLSw, you cannot use DLSw ethernet redundancy. As you do not use mac-address to modify the MAC address for the ethernet interfaces, there is no redundancy at all for the downstream PUs.

I wonder if the customer wants redundancy for the downstream PUs. If they do, the only solution I can think of is to use DLUR (SNASw). You use mac-address on ethernet interface to set the ethernet interface on both router the same. Then, you run HSRP. The active HSRP router will pick up all LLC2/DLUR session. Once the active HSRP router goes down, the backup HSRP router will pick up the circuit. I think that THERE MAY BE A CHANCE THAT DSPU may work with HSRP and mac-address. However, I do not think that any one has tried it

New Member

Re: DSPU over 2 DLSW router on same ethernet

If I have well understood with DSPU I cannot have redundancy even by configuring the same mac-address on both ethernet. I don't understand why I have to configure the same mac-address even with HSRP while there is already one used by both routers.

Silver

Re: DSPU over 2 DLSW router on same ethernet

If you use HSRP and SNASw, only the active HSRP router will handle all DLUR session for the downstream PUs. I have never tried HSRP and DSPU. If the same concept works, you will have redundancy. i.e. the active HSRP router will handle all DSPU sessions. Of course, the LUs on downstream PUs will have different LUs on different routers.

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