BTEL - CGN Notes

F5 BIG-IP Glossary

Trunk = LAG

Interfaces = Physical ports

Vlans = Logical interfaces

CGN Virtual Server = Internal CGN configuration that defines internal IP's.

Source Translation = External CGN configuration that defines public IP pools and NAT Mode

CGN Policy = Ties the Virtual Server to the Source Translation configuration.

F5 BIG-IP Notes:

To access routing shell on BIG-IP servers SSH in and run:

imish

For OSPF between BIG-IP and BNG we're using NBMA with defined neighbors. The BIG-IP servers filter all outbound route advertisements so they will only use OSPF to receive routes. They need routes in order to know route to the active BNG router.

To prevent an issue where OSPF routes would not be installed in the BIG-IP servers, the neighbor statements in the BNG must declare the BIG-IP neighbors as priority 0. Without this, the DR election doesn’t work as expected.

Deterministic NAT will not work without setting the CMP hash on the internal and external vlans inside the BIG-IP server

External CMP hash = Destination Address

Internal CMP hash = Source Address