Sample Configuration for BGP with Two Different Service Providers (Multihoming)

No need to explain, click the following link

http://www.cisco.com/en/US/tech/tk365/technologies_configuration_example09186a008009456d.shtml

Multicasting querier Highest or Lowest IP?

According to cisco
http://www.cisco.com/en/US/docs/ios_xr_sw/iosxr_r2.0/multicast/command/reference/3mrigmp.html

The designated router for a LAN is the only router that sends IGMP host-query messages:

•For IGMP Version 1, the designated router is elected according to the multicast routing protocol that runs on the LAN.

•For IGMP Versions 2 and 3, the designated querier is the highest IP-addressed multicast router on the subnet.

If the router hears no queries for the timeout period (controlled by the query-timeout command), it becomes the querier

IP POLICY

It is important to remember that Ip policy apply to the ARRIVING interface.



http://www.cisco.com/en/US/docs/ios/12_0/qos/configuration/guide/qcpolicy.html
Enable PBR
To enable PBR, you must create a route map that specifies the match criteria and the resulting action if all of the match clauses are met. Then you must enable PBR for that route map on a particular interface. All packets arriving on the specified interface matching the match clauses will be subject to PBR.

BGP - difference between local preference and weight attribute

The major difference between the Weight and LOCAL_PREF attributes is that when the LOCAL_PREF attribute is changed, that change is reflected throughout the AS. The new LOCAL_PREF value will be advertised to all other routers in the AS, as compared to the Weight attribute, which is locally significant only.