3com 6.0.4.6 User Manual
Points to Note When Using the WXR100, WX1200, WX4400, or WX2200
17
Distributed MAP Best Practice When Using STP
A Distributed MAP is a leaf device. You need not
enable STP on the port directly connected to the MAP.
enable STP on the port directly connected to the MAP.
If Spanning Tree Protocol (STP) is enabled on the port
that is directly connected to a Distributed MAP, you
might need to change the STP configuration on the
port to allow the MAP to boot.
that is directly connected to a Distributed MAP, you
might need to change the STP configuration on the
port to allow the MAP to boot.
STP on a port directly connected to a Distributed MAP
can prevent the MAP from booting.
can prevent the MAP from booting.
Use IGMP Snooping Effectively
Using IGMP (11909, 12863, 12866)
MSS supports the Internet Engineering Task Force
(IETF) draft draft-ietf-magma-snoop for controlling
the forwarding of IP multicast traffic by a Layer 2
switch. The draft mandates the use of a 0.0.0.0
source IP address if no IP address is available on the
switch for the subnet. However, some multicast rout-
ers and even other Layer 2 switches report errors in
the presence of the 0.0.0.0 source IP address.
(IETF) draft draft-ietf-magma-snoop for controlling
the forwarding of IP multicast traffic by a Layer 2
switch. The draft mandates the use of a 0.0.0.0
source IP address if no IP address is available on the
switch for the subnet. However, some multicast rout-
ers and even other Layer 2 switches report errors in
the presence of the 0.0.0.0 source IP address.
Apply the following methods to use IGMP snooping
effectively:
effectively:
■
Set IP addresses on all VLAN interfaces. This
straightforward workaround prevents most known
issues. If querier functionality might be needed,
ensure that the IP address of the WX switch VLAN
is higher than the address of any multicast router
servicing the same subnet.
straightforward workaround prevents most known
issues. If querier functionality might be needed,
ensure that the IP address of the WX switch VLAN
is higher than the address of any multicast router
servicing the same subnet.
■
Consider disabling IGMP proxy reporting. The
IGMP proxy reporting function is enabled by
default, but some multicast routers do not accept
IGMP proxy reporting function is enabled by
default, but some multicast routers do not accept
reports using a 0.0.0.0 source IP address. In this
case, either assign an IP address to the VLAN inter-
face on the WX switch or disable IGMP proxy
reporting. To disable proxy reporting, use the
command set igmp proxy-report disable.
case, either assign an IP address to the VLAN inter-
face on the WX switch or disable IGMP proxy
reporting. To disable proxy reporting, use the
command set igmp proxy-report disable.
Disabling proxy reporting can increase IGMP over-
head traffic to the multicast router.
head traffic to the multicast router.
■
Enable the IGMP querier only if needed. The IGMP
pseudo-querier function is disabled by default.
Enable it only if the source of a multicast stream is
on a subnet the WX switch is also connected to. If
this is the case, you must assign an IP address to
the VLAN interface. The IP address must be higher
than the IP address of the querier multicast router
on the same subnet. To enable the IGMP
pseudo-querier, use the command set igmp
querier enable.
pseudo-querier function is disabled by default.
Enable it only if the source of a multicast stream is
on a subnet the WX switch is also connected to. If
this is the case, you must assign an IP address to
the VLAN interface. The IP address must be higher
than the IP address of the querier multicast router
on the same subnet. To enable the IGMP
pseudo-querier, use the command set igmp
querier enable.
■
Disable multicast router discovery. This multicast
router solicitation protocol (part of
draft-ietf-magma-snoop) is known to cause error
messages with other IGMP snooping switches and
multicast routers. To disable the protocol, use the
command set igmp mrsol disable. (The protocol
is disabled by default in the current software
version.)
router solicitation protocol (part of
draft-ietf-magma-snoop) is known to cause error
messages with other IGMP snooping switches and
multicast routers. To disable the protocol, use the
command set igmp mrsol disable. (The protocol
is disabled by default in the current software
version.)
User ACLs Require Explicit Source and Destination
Addresses
Addresses
A user ACL is an ACL that is applied to a specific user-
name. You can apply ACLs to a user’s inbound or out-
bound wireless traffic. For a user ACL to take effect,
you must explicitly set both the source and destina-
tion addresses in the ACL.
name. You can apply ACLs to a user’s inbound or out-
bound wireless traffic. For a user ACL to take effect,
you must explicitly set both the source and destina-
tion addresses in the ACL.