The basic concept of a .VRRP
VRRP (Virtual Router Redundancy Protoco1, referred to as VRRP) can be good to avoid static defects specified gateway.
1. Overview agreement. In VRRP agreement, there are two important concepts: VRRP virtual router and router, the master router and the backup router.
VRRP routers are running VRRP router is a physical entity, means the VRRP virtual router protocol created is a logical concept.
A group of VRRP router to work together to form a virtual router. The external performance virtual router has a unique fixed
Logical router IP address and MAC address. The role of the router in a VRRP group has two mutually exclusive: the master router
And backup router, a VRRP group and only one in the master role of the router, there may be one or more backup in
Router role. VRRP protocol using a selection policy selected as the master router from the group, responsible for the corresponding ARP and IP forwarding number
According to the package, the other group as a standby routers in a standby state. When for some reason the master router fails,
Backup router can postpone a new master router when a few seconds. Because of this very rapid switching and do not change the IP address and MAC
Address, so the system is transparent to the end user.
2. works. VRRP router has a unique identifier: VRID, the range of 0-255. The router is the only external performance
Virtual MAC address format, the address is 00-00-5E-00-01- [VRID].
Master router is responsible for answering ARP requests to do with the MAC address. Thus, switch anyway, to ensure that the terminal device is unique
The same IP and MAC addresses, reducing the impact of the handover of the terminal device.
Two .BGP agreement
BGP is an external routing protocol for passing routing information between AS
It is a distance vector routing protocol, to avoid the generation of a loop from the design
Routing incidental attribute information
Transport protocols: TCP, port 179 supports CIDR (Classless Inter-Domain Routing)
Routing updates: send only incremental routes
Rich routing and route filtering policy
Reproduced in: https: //blog.51cto.com/14213970/2404225