URGENT FIREWALL QUESTION.

[thaar_altaiey]

i am studying severall offers to buy a new entripreies CISCO based network. some offers suggest me to use CISCO Router 2821XM /3700 series. both containes firwall with IOS. my question: what is the main technical differences between using the firewall within the router s/w or as seperated PIX H/W, and which PIX series is better?

any info are appericated.

thanks

[thaar_altaiey]

one more question please, which CISCO PIX can support powerful antivirs through the entriprise network.

thanks