BROCADE IP PRIMER

URL SwitchingURL SwitchingURL switching provides the capability to load balance based on Layer 7 information.Specifically, we're referring to the user-requested Uniform ResourceLocator (URL). The URL is the full path of the item being requested. For example,Brocade's main web site is http://www.brocade.com/. The web pagediscussing the latest ServerIron products is http://www.brocade.com/products-solutions/products/application-delivery/serveriron-adx-series/.Notice that it's similar, but there's some additional information beyond the firstsingle slash (/). Technically, the “www.brocade.com” is considered the ServerRequest, and the “/products-solutions/products/application-delivery/serveriron-adx-series/” is considered the URL.In a nut shell, URL switching allows the ServerIron to load balance to some realservers if one type of URL is received, to other real servers if another type ofURL is received, and to yet others if another type of URL is received. When theclient requests a web page, the URL the client is requesting is in the HTTPheader. According to policies that you define, the ServerIron will load balanceto different servers based on the on the URL in the incoming HTTP header.Let's say we have six real servers. Two are general web servers. Two are imageservers. And two are CGI application servers. We'd like to bind all six of theseservers to the same virtual server, but we only want static HTML content(located in the “/www” directory) to be served by the web servers, imagesserved by the image servers, and CGI applications handled by the applicationservers.There are a set of rules that define the conditions for URL switching. We startby creating URL rules and specify a matching method. The method “prefix”tells the policy to look at the beginning of the URL. The next line tells the policywhat to look for. In this case, we told it to look for any URLs starting with “/www”. The next rule is using the method “suffix”. This is telling the rule to lookat the very end of the URL. We know that our images are all GIF images, andthey all have the filename suffix “.gif”. The last rule method is called “pattern”.This tells the policy to look for whatever we specify anywhere within theURL, in this case cgi.SLB-ServerIron#conf tSLB-ServerIron(config)# csw-rule r1 url prefix "/www"SLB-ServerIron(config)# csw-rule r2 url suffix ".gif"SLB-ServerIron(config-)# csw-rule r3 url pattern "cgi"SLB-ServerIron(config)#csw-policy p1SLB-ServerIron(config-csw-p1)# match r1 forward 1SLB-ServerIron(config-csw-p1)# match r2 forward 2SLB-ServerIron(config-csw-p1)# match r3 forward 3SLB-ServerIron(config-csw-p1)#default forward 1It's important to be careful to place default policies or default groups in yourCSW, but look out for loops.Brocade IP Primer 363