CSS 11503 Support for RHI

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Feb 20th, 2008
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Can anyone confirm if the CSS 11503 supports RHI (Route Host Injection). I have seen a slide that gives an example of it but all my research indicates it is only supported on the CSM with the 6500.

Any feedback would be appreciated.

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Gilles Dufour Thu, 02/21/2008 - 05:09
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Only CSM or ACE since the route is injected in the MSFC routing table.

CSS does not have an MSFC :-)

The CSS can inject a route into OSPF, but it is not conditional. Just normal static route injection.


billsayegh Thu, 02/21/2008 - 13:44
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Thanks for the reply

Can the GSS also do RHI or is it only using DNS for failover.

From what I can work out we have two options for data centre to data centre failover of servers.

1. GSS with DNS

2. ACE or CSM with RHI

What I like about RHI is that it is not fixed to DNS and any problems with caching of clients and some of our clients also use static IP address.

If we go down the RHI track from your previous email we only have two options the CSM + 6500 or the ACE.

Do all the ACE models support RHI.


billsayegh Thu, 02/21/2008 - 20:06
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With regard to the ACE does the ACE 4700 appliance support RHI or is it the ACE module in the 6500 only supports RHI.

Does the ACE support DNS for data centre redundancy similar to the GSS and is it supported on the 4700 appliance or just the ACE in the 6500.

Appreciate any advise.

Gilles Dufour Fri, 02/22/2008 - 00:41
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no RHI on the appliance.

Once again, RHI only works with an MSFC.

No gss/dns functions inside the ACE module or appliance.

But the GSS will work with the ACE module or appliance w/ version ACE2.0


Gilles Dufour Fri, 02/22/2008 - 01:19
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I have to correct this statement.

Sb told me this was a conditional advertisement.

The doc was not clear on the subject so I went in the lab to doublecheck, and indeed, the route will not be adertised if the content rule is down.


Gilles Dufour Fri, 02/22/2008 - 04:55
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so to be clear the CSS supports RHI with the ospf advertise command.

The route is injected as an external ospf route.


billsayegh Sun, 02/24/2008 - 14:13
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Then this achieves the same result as the CSM with MSFC. If the CSS sits in front of the servers and is poling them with the keepalive and the VIP goes down it will not advertise the VIP as an OSPF exteranl type 2.

So for this solution we could have two CSS at data centre A poling the servers and advertising the VIP as an E2 to the core MSFC router and the backup data centre B CSS Poling the backup servers and advertising the VIP as an E2 with higher metric.

The result will be that if the VIP in the primary data centre is down, then traffic would go to the backup servers in the backup data centre.

In the primary data centre we would have two CSS runing HSRP for the VIP so that if one CSS failed traffic would go to the backup VIP.

This is what the slide shows.

So to be clear the CSS does support conditional advertisement of the VIP as a host route and hence achieves the same result as the MSFC.

This is what the slide shows.

Thank you very much for taking the time to test this and being thorough in your answer.


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