you can use object tracking features in policy routing.http://www.cisco.com/en/US/partner/about/ac123/ac114/ac173/Q2-04/department_techtips.htmlhttp://www.cisco.com/univercd/cc/td/doc/product/software/ios122/122newft/122t/122t15/fthsrptk.htm
the ToS field is 1 byte long 0-255. your tos value will depends on the Qos techniques (ip precendence or DSCP)ip prec occupies the first 3 bits of the ToS field. So for 'critical' ip prec packets, the ToS value will be 10100000 = 160http://www.cisco....