Vrrp Components - Lenovo Flex System Fabric CN4093 Application Manual

VRRP Components

Virtual Router
Virtual Router MAC Address
Owners and Renters
Master and Backup Virtual Router
Virtual Interface Router
472
CN4093 Application Guide for N/OS 8.2
Each physical router running VRRP is known as a VRRP router.
Two or more VRRP routers can be configured to form a virtual router (RFC 2338).
Each VRRP router may participate in one or more virtual routers. Each virtual
router consists of a user‐configured virtual router identifier (VRID) and an IPv4
address.
The VRID is used to build the virtual router MAC Address. The five highest‐order
octets of the virtual router MAC Address are the standard MAC prefix
(00‐00‐5E‐00‐01) defined in RFC 2338. The VRID is used to form the lowest‐order
octet.
Only one of the VRRP routers in a virtual router may be configured as the IPv4
address owner. This router has the virtual router's IPv4 address as its real interface
address. This router responds to packets addressed to the virtual router's IPv4
address for ICMP pings, TCP connections, and so on.
There is no requirement for any VRRP router to be the IPv4 address owner. Most
VRRP installations choose not to implement an IPv4 address owner. For the
purposes of this chapter, VRRP routers that are not the IPv4 address owner are
called renters.
Within each virtual router, one VRRP router is selected to be the virtual router
master. See "Selecting the Master VRRP Router" on page
the selection process.
Note: If the IPv4 address owner is available, it will always become the virtual router
master.
The virtual router master forwards packets sent to the virtual router. It also
responds to Address Resolution Protocol (ARP) requests sent to the virtual routerʹs
IPv4 address. Finally, the virtual router master sends out periodic advertisements
to let other VRRP routers know it is alive and its priority.
Within a virtual router, the VRRP routers not selected to be the master are known
as virtual router backups. Should the virtual router master fail, one of the virtual
router backups becomes the master and assumes its responsibilities.
At Layer 3, a Virtual Interface Router (VIR) allows two VRRP routers to share an IP
interface across the routers. VIRs provide a single Destination IPv4 (DIP) address
for upstream routers to reach various destination networks, and provide a virtual
default Gateway.
473 for an explanation of