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Groundbeef79
Enthusiast
Enthusiast

Equallogic Replication for SRM, is my router borked?

This is probably more a networking/Equallogic SAN question than anything.  We have a PS6100X and a PS6100XV with replication configured between the two on a 100 Mbit metro ethernet connection.  At site A (with the 6100X) we have a Cisco 2851 router.  At site B, there is a Cisco 2811.  We plan to implement Certeon's aCelera in the coming weeks as part of our SRM deployment.  During replications, the CPU on the 2811 spikes to near 100%.  Also, I'm only seeing WAN speeds of around 30 Mbit instead of the 100.  I'm starting to question if the 2811 is beefy enough to handle the replication.  Anyone out there with experience using Certeon?  Dell sold this solution to us as a package deal more or less.  The Certeon will cut down on the amount of data to be replicated, but I'm worried about that router on the other side.  Thoughts anyone?  Is the 2811 up to snuff or should we look at upgrading?  Anyone do this?  Should I just wait until the Certeon is in place AND SRM, then look at the router?

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Kyptiano
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Contributor

Hi there, I have seen this before, below is an explanation to why you are seeing a throttle on the WAN.

Technically you could route and make the connection work, but you will likely lose out on performance as the router would not be able to handle the connection at wire (full) speed. Check the throughput of the router on Cisco's data sheets. The 2800 series is not recommended even for E3 links. On Cisco's site you get the designed throughput of each router models in pps (packets per second) and based on that you can compare what throughput you can get. The 2800 series is designed for multiple E1 links, it’s certainly not designed for 100 Mbps connections, even if it does come with a Gigabit Ethernet interface by default. What counts is not the interfaces that are in there but the speed that the processor and backplane can handle. Low end routers use the software and the CPU of the router to handle packet forwarding so speed is limited. If you wanted full routing features and wire speed, the 7200 series routers would be the safe option. The 3845 might work but even that would be pushing it.

If your connection is delivered via fast Ethernet, a Layer-3 switch like a 3750 or 3560 would be perfectly able to handle the traffic especially since you are not going to use NAT or Firewall features. The L3 switch with Enterprise service image will be able to run any routing protocol including BGP etc and also process access-lists in hardware at wire speed. Compared to the similarly priced low-end router the L3 switch can handle a lot more capacity since unlike the 2800, it does its packet forwarding using a hardware ASIC, so it can support the full 100 Mbps at wire speed. The only drawback is that you wont have certain WAN routing features that you get on the router such as NAT or certain types of QOS.

The 28xx is oriented for multiple E1 (and/or Serial (v.35,x.21etc)) links, not for 100 Mbps connection. It would be better to use the 7200 series routers for full 100 mbps connection.

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Groundbeef79
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Enthusiast

Thanks for the reply!  I talked to one of our vendors about this issue as well.  I did not know this, but we're also running an AES 256 encrypted VPN from our site to the other.  All of our traffic traverses this VPN.  He said that could be another reason we're seeing this.  Would you think that to be the case as well?  It sounds like from what you're saying, the 2800 series just isn't good enough to do this.  I don't think using a switch would be an option for us as we have multiple routed networks, VoIP services, etc. all passing through those routers.

What you say sort of makes sense because at the time when we bought these, I don't even remember what we had router-wise, but we did have an analog phone system.  It previously was connected via multiple T1's to multiple locations.  When we brought in our metro ethernet connections, they had to do some sort of weird emulation.  I don't know what because I'm not a router guy.

Sounds like the vmware forum probably isn't the place for this and we should be seeking some expert router advice.

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