36 lines
1.8 KiB
Plaintext
36 lines
1.8 KiB
Plaintext
VRRP daemon (vrrpd) is an RFC 2338 compliant implementation of
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the Virtual Router Redundancy Protocol (VRRP). The Virtual Router
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Redundancy Protocol is designed to eliminate the single point of
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failure associated with statically routed networks by automatically
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providing failover using multiple LAN paths through alternate routers.
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As specified in RFC 2338, VRRP uses an election protocol that
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dynamically assigns responsibility for a virtual router to one of the
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VRRP routers on a LAN. When a VRRP router controls the IP address(es)
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associated with a virtual router, it is called the Master. The Master
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continues to forward packets sent to these IP addresses until it has a
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problem that causes the VRRP routers to hold an election. The election
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process provides dynamic failover by electing a new Master should the
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existing Master become unavailable.
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The virtual router associated with each alternate path under VRRP uses
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the same IP address and MAC address as the routers for other paths. As
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a result, the host's gateway information does not change, no matter
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what path is used. Because of this design, VRRP-based redundancy
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significantly reduces administrative overhead when compared to
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redundancy schemes that require hosts to be configured with multiple
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default gateways.
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The primary function of the Virtual Router Redundancy Protocol is to
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provide routing redundancy for specific IP addresses. In addition to
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this primary function, RFC 2338 also states that the protocol should:
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* Minimize the duration of black holes.
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* Minimize the steady state bandwidth overhead and processing
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complexity.
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* Function over a variety of multiaccess LAN technologies that support
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IP traffic.
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* Provide for election of multiple virtual routers on a network for
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load balancing.
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* Support multiple logical IP subnets on a single LAN segment.
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