The standard action, as performed by router software (such as Cisco IOS), is to select the next hop address and the output device. I will refer to this action as a "match & set" style of action. However, Linux takes a much more flexible approach. In Linux, there are several actions to choose from. The default action performs a route lookup from a specified destination-based routing table. The match & set action then becomes the simplest case of Linux route selection, which is realized when the specified destination-based routing table contains only a single default route. Linux supports multiple routing tables, containing multiple standard destination routes. Bear in mind that each of these routing tables is the same as the entire routing table for any other OS. Linux effectively provides 255 Ciscos to choose from. (For number freaks, Linux 2.2.12 supports 255 routing tables, 255 aggregate realms, and 232 (4294967296 decimal) policy rule priorities.
[toc:faq]The ProblemOn traditional switches whenever we have a trunk
interface we use the VLAN tag to demultiplex the VLANs. The switch needs
to determine which MAC Address table to look in for a forwarding
decision. To do this we require the switch to do...
[toc:faq]Introduction:Netdr is a tool available on a RSP720, Sup720 or
Sup32 that allows one to capture packets on the RP or SP inband. The
netdr command can be used to capture both Tx and Rx packets in the
software switching path. This is not a substitut...
IntroductionOSPF, being a link-state protocol, allows for every router
in the network to know of every link and OSPF speaker in the entire
network. From this picture each router independently runs the Shortest
Path First (SPF) algorithm to determine the b...