RuggedCom RS1600 Manuel D’Utilisation
RuggedSwitch
™ User Guide
Combined Router And Switch IGMP Operation
This section describes the additional challenges of multiple routers, VLAN
support and switching.
support and switching.
Producer P1 resides upon VLAN 2 while P2 resides upon VLAN 3. Consumer C1
resides upon both VLANs whereas C2 and C3 reside upon VLANs 3 and 2,
respectively. Router 2 resides upon VLAN 2, presumably to forward multicast
traffic to a remote network or act as a source of multicast traffic itself.
resides upon both VLANs whereas C2 and C3 reside upon VLANs 3 and 2,
respectively. Router 2 resides upon VLAN 2, presumably to forward multicast
traffic to a remote network or act as a source of multicast traffic itself.
Multicast
Router 1
P1
C1
C2
C3
Switch
Multicast
Router 2
VLAN 2,3
VLAN 3
VLAN 2
VLAN 2
VLAN 2
P2
VLAN 3
VLAN 2
Figure 43: IGMP Operation Example 2
Starting Up
Multicast routers use IGMP to elect a master router known as the querier. All
other routers become of non-queriers, participating only forward multicast traffic.
If both switches and routers are present, a router always becomes the querier.
Routers and switches can always distinguish each other from the source IP address
in the IGMP query. A router uses its own source address while the switch always
uses an address of 0.0.0.0 for queries, joins and leaves.
other routers become of non-queriers, participating only forward multicast traffic.
If both switches and routers are present, a router always becomes the querier.
Routers and switches can always distinguish each other from the source IP address
in the IGMP query. A router uses its own source address while the switch always
uses an address of 0.0.0.0 for queries, joins and leaves.
At startup a switch in active IGMP mode will begin generating general
membership queries for each VLAN on each port every switch query interval. If
the switch detects a querier router on a particular VLAN it will stop generating its
own queries and relay those from the querier.
membership queries for each VLAN on each port every switch query interval. If
the switch detects a querier router on a particular VLAN it will stop generating its
own queries and relay those from the querier.
A switch starting up in passive mode will simply wait for queries from a router.
In this example we will assume that the two routers agree that router 1 is the
querier for VLAN 2 and router 2 is simply a non-querier. In this case, the switch
will periodically receive queries from router 1 and, thus, maintain the information
which port links the multicast router. However, the switch port that links to router
2 must be manually configured as “router port”, otherwise, the switch will not
send neither multicast streams or joins/leaves to router 2.
querier for VLAN 2 and router 2 is simply a non-querier. In this case, the switch
will periodically receive queries from router 1 and, thus, maintain the information
which port links the multicast router. However, the switch port that links to router
2 must be manually configured as “router port”, otherwise, the switch will not
send neither multicast streams or joins/leaves to router 2.
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