Irule question about switch -glob $host

Assuming that xx represent different numbers then you can best explain it as..

    when HTTP_REQUEST { 
    set host [HTTP::header host] 
    switch -glob $host {

Take the host entry and use it as a switch statement target

   "dc.bangkokair.com" {pool cp-2sg-as-t1-mingo-prod_pool_81xx  }
    "sws-pg.as.havail.sabre.com" {pool cp-2sg-as-t1-mingo-prod_pool_81xx  }
    default { 
        pool cp-2sg-as-t1-mingo-prod_pool_81xx  
    } 

Search for the following and provide the appropriate pool of servers...

• Matched dc.bankokair.com select pool cp-2sg-as-t1-mingo-prod_pool_81xx.
• Matched sws-pg.as.havail.sabre.com select pool cp-2sg-as-t1-mingo-prod_pool_81xx.
• If no matches select pool cp-2sg-as-t1-mingo-prod_pool_81xx

The switch -glob allows you to do simple pattern matching as follows...

Ends with "*.bankokair.com"

Starts with "www.*"

Contains "*.bankokair.*"

Note the periods (.) have no special meaning. They just represent that character.

From a high level perspective, if they type in http(s)://dc.bangkokair.com/* the name is mapped to the IP address (or external NAT) of this virtual server. Same for http(s)://sws-pg.as.havail.sabre.com/* but it will accept any name given the default pool selection.