BinTec RS353j User Manual page 490

19 Local Services
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It guarantees that if the active route fails, another router takes over the function of the failed
device. The time that each router is active is determined by the priority assigned to the
router.
Let us take the example of a simple scenario, in which gateway A provides Internet access
for the hosts in a LAN. If this gateway fails, all hosts cannot access the Internet and their
routes are configured statically. To allow the hosts continued access to the Internet, gate-
way B offers all hosts in the LAN the service that gateway A previously performed. All the
tasks of a "virtual router" and the switching of services from one gateway to the other are
controlled by the BRRP redundancy procedure.
The BRRP conforms to the specifications in RFC 2338 and the relevant Internet draft (see
www.ietf.org ).
The configuration of the router redundancy procedure is carried out in the following steps:
• Configuration of the interface via which the BRRP advertisement data packets are sent.
Note
This interface is used to transmit the BRRP advertisement data packets and possibly
to transmit keepalive monitoring data packets. Another interface must be configured in
the next step to transmit the usage data.
Configuration of the advertisement interface is performed in the Local Services->BRRP-
>Virtual Router->New menu under BRRP Advertisement Interface.
Only the active router in the router group sends advertisement data packets. The IPv4
multicast address 224.0.0.18 is used as the destination address for all routers in the
group. All passive routers in the group must monitor this address so that if the advertise-
ment data packets are not received that can react according to their priority and BRRP
configuration.
• Configuration of the interface for transmitting usage data (configuration of the virtual in-
terface).
A virtual interface is activated and deactivated by assigning it to a virtual router over the
BRRP router redundancy protocol.
Configuration is performed in the Local Services->BRRP->Virtual Router->New->Eth-
ernet Interface menu.
In this step, you configure the IP address settings and assign the interface to a virtual
router. The properties of the virtual router (e.g. the priority) are also defined here.
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