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