It looks like the primary question here is performance, in which case:Performance is not an issue, so long is it is sufficient. In the case of CSS 11000 and Alteon, performance fall within the same order of magnitude (supporting web sites with several billion hits per day.) F5 does not have sufficient performance, due to platform and OS limitations (I’ve heard as low as 50 connections per second in complex configurations). The Cisco CSM posts up over 10x the performance at 200k flows/second.
Typically the primary concern is features, then CSS 11000 switches lead with a wide and flexible array of features that are not only helpful to network and web administrators, but well integrated too. CSS 11000 switches offer configuration through CLI, Web GUI, and XML. CSS 11000 collects statistics that can be exported to non-Cisco applications for billing and management.
The CSS11000 also supports URL load balancing and HTTP header balancing within one content rule, with complex matching. Further, it supports user agent, pragma/no-cache, host field, cookie field, language field, accept, accept charset, accept-encoding, and Connection within the http header field.
In addition, the CSS11000 matches up to 128 bytes with support of wildcards anywhere within the string.On the other hand, Nortel (Alteon) - HTTP header load balancing is not supported on the same VIP as URL load balancing. Eg. This means that a simulated WAP user cannot be directed to a server while load balancing "normal" browsers to their servers based on URL without using two separate VIPs. Only ONE http header load balance is supported on the entire switch. This limits you to either User Agent (WAP, Netscape, IE, Palm, etc), OR pragma/no cache (do not send the user to cache, allow (the user) to go to the origin), or Host field (allowing you to direct on domain name), or Cookie. Also, Nortel does not support the language field.
In regards to F5, many of the performance claims are based on HTTP 1.0 requests (most web sites today are not using HTTP 1.0), Many emerging applications rely on HTTP 1.1 rather than HTTP 1.0. Also, the BIG-IP cannot spoof the connection to detect the URL, cannot do NAT on the flow, and cannot maintain states for persistent connections.
Overall, I think CSS switches are the lowest cost to own, and most effective of all the load balancing platforms on the market.
