15.1.9 Notes on using VRRP
- <Structure of this section>
(1) About coexistence with other functions
(a) Coexistence with Layer 2 Switch Function
See "Configuration Guide: Coexistence of Vol.1" "22.3 Layer 2 Switch Function and Other Functions".
(b) Coexistence with Layer 2 authentication
[5.2.1 See Coexistence of Layer 2 Authentication with Other Functions.
(c) Coexistence with High Reliability Functions by Redundant Configuration
The following tables show the high-reliability features of redundant configurations that are limited to coexist with VRRP.
|
Functionality |
Restrictions |
|---|---|
|
GSRP |
Cannot be used |
(2) About ADVERTISEMENT Packet-Send Interval
In the cases listed below, the VRRP advertisement packets to be sent and received by the Switch might be dropped or their processing might be delayed, resulting in state transitions. If state transitions occur frequently, specify a longer sending interval for the VRRP advertisement packets.
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When the CPU load on the Switch is excessive
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When too many virtual routers are configured on the Switch
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When network load is excessive
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When a virtual router consists of three or more Switches
(3) Monitoring Multipath Routes by VRRP Polling
VRRP polling cannot be used to monitor multipath routes.
(4) Linking IPv6 VRRP and RA
When router advertisement (RA) is enabled on an interface on which IPv6 VRRP is configured, RA operates as follows in conjunction with VRRP:
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RA distributes information only when it resides on the IPv6 VRRP master router.
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The source MAC address in the MAC header in an RA packet is the virtual MAC address of the virtual router.
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The source IPv6 address in the IPv6 header in an RA packet is the virtual IPv6 address of the virtual router.
In this way, a terminal can use the IPv6 automatic configuration functionality to specify a virtual router as its default gateway.
However, the operation of a network with RA might be adversely affected by the operation of a terminal in the following cases:
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When multiple virtual routers are configured on a single interface, RA operates only with the master router with the smallest VRID. If you intend to use VRRP for load balancing, manually specify the default router on each terminal.
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When you specify a global address instead of a link-local address as the virtual IPv6 address, you need to specify a link-local address that is specific to an interface as the source IPv6 address of RA, not the virtual IPv6 address. This is because RA requires a link-local address as the source IPv6 address. In this case, VRRP and RA will not work together. If you want to use VRRP in conjunction with RA, do not specify a global address as the virtual IPv6 address.
(5) About Configuring Follow Virtual Routers
Note the following points when configuring a follower virtual router:
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When using the same virtual router ID, make sure that they are grouped and belong to the same group.
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When the virtual router ID used by the Switch and another switch are the same, Layer 2 forwarding cannot be performed on the Switch for frames that are destined for the associated virtual MAC. Use a virtual router ID that differs between the Switch and another Switch.