Load sharing and redundancy scheme

DETAILED DESCRIPTION An invention is described herein that provides load sharing and redundancy in a network.
This is accomplished, according to one embodiment, through the use of a master router and a slave router operating in the same chassis and having a shared set of interfaces.
Prior to failure of the master router, the master router communicates shared state information to the slave router.
In addition, the slave router operates in "standby mode" to obtain information from the shared set of interfaces.
In this manner, the switchover time required to switch from the master router to the slave router upon failure of the master router is significantly reduced.
According to one aspect of the invention, a default gateway is associated with both the master router and the slave router.
This is accomplished by assigning a shared IP address and a shared MAC address to both a first router and a second router so that the shared IP and MAC addresses are shared between the first router and the second router.
Additionally, a first MAC address is assigned to the first router and a second MAC address is assigned to the second router.
The default gateway is configured on the hosts such that a default gateway IP address is associated with the shared IP address.
The shared IP and MAC addresses are associated with one of the routers (e.
g.
, the first router or master router).
When the master fails, the slave takes over both the shared IP address and the shared MAC address.
In order to route traffic, there are three layers of protocol: a physical layer, a data link layer, and a network layer.
The data link layer is often referred to as "layer 2" while the network layer is often referred to as "layer 3.
" The responsibility of the data link layer is to transmit chunks of information across a link.
The responsibility of the network layer is to enable systems in the network to communicate with each other.
Thus, the network layer finds a path or "shortcut" through a series of connected nodes that must forward packets in the specified direction