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HP ProCurve 5308XL-48G Supplementary Manual: Igmp; Guaranteed Minimum Bandwidth (gmb)

Hp procurve 5308xl-48g: supplementary guide.
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VLANs can overlap on a single port. For example, it may be advantageous to have a server
connected through a single port to be a member of two different VLANs
such that two different
groups of PCs can access the same server, but the two groups of PCs cannot talk directly with
each other.
IEEE 802.1Q VLAN Support
The ProCurve 5300xl Switch Series support the IEEE 802.1Q VLAN tagging standard. The
ProCurve 5300xl Switch Series can have multiple VLAN traffic streams share a single physical
link. 802.1Q also allows interoperability at this level between different vendors in a standards-
based way. End-to-end VLAN designation is also greatly simplified through the 802.1Q tag,
particularly if GVRP, discussed in the next section, is used.
Ports with only a single VLAN designation can be designated as untagged ports. Packets leaving
these ports will not be 802.1Q tagged. VLAN continuity from switch-to-switch must be manually
maintained at each switch if untagged ports are used.
GVRP—GARP VLAN Registration Protocol is a standard under 802.1Q that provides a facility to
dynamically configure a VLAN on switches throughout a Layer 2 domain when that VLAN has
been statically configured on at least one switch in the domain. The intention with GVRP is to
automatically interconnect a VLAN that is manually configured on two switches that are not
contiguous in a Layer 2 domain. This greatly reduces the administrative overhead of having to
define VLANs in all the intermediate switches between two VLAN islands that need to be
interconnected. GVRP will also delete a dynamic VLAN on any switch port that hasn't heard
externally from the VLAN in the last 10 seconds.
GVRP is particularly advantageous in environments using 802.1X, for network login. In 802.1X,
as a user is authenticated to the switch from the RADIUS server, a VLAN membership can also
be indicated. This allows the network manager to assign a particular user to a particular VLAN
to establish the network services available for that user. For example, when the user logs in,
she can be placed in her own VLAN along with the servers and storage that contains the
services that user is allowed to have. One of the advantages of 802.1X is the ability for the user
to login anywhere in the network. If she is assigned to a VLAN that also has services members,
that VLAN will have to be defined all along the path between the user and those services. GVRP
will automatically do this. GVRP will also delete that VLAN along the path once it is no longer
The ProCurve 5300xl Switch Series has a configuration default of 8 VLANs maximum that can be
defined. If GVRP is enabled, the 'maximum VLANs to support' value should be configured in
most cases to be the maximum number of VLANs expected in the entire network environment
supported by GVRP. This will provide space for dynamic VLAN definitions that come about
through GVRP.


Internet Group Multicast Protocol (IGMP) is a multicast control protocol that builds delivery
paths through the switch network. The switch eavesdrops on IGMP traffic so that it knows which
ports are part of which multicast groups. If there is no multicast router available, the ProCurve
5300xl Switch Series can act as an IGMP querier to learn which end nodes have subscribed to
which multicast streams. The switch can then direct a specific multicast stream to only those
switch segments that have nodes that have joined the multicast group associated with that
stream. Configuration of this feature is a single check box to turn it on. The ProCurve 5300xl
Switch Series supports IGMP version 3 by recognizing and processing IGMPv3 joins. Version 3 is
backwards compatible with versions 1 and 2.
The ProCurve 5300xl Switch Series supports a maximum of 389 IGMP groups.

Guaranteed Minimum Bandwidth (GMB)

Guaranteed Minimum Bandwidth (GMB) provides a certain minimum consideration for traffic
priorities vying for output from the switch. For instance, if the customer has directed all of his
VOIP traffic to be 802.1p priority 7 (high priority), Guaranteed Minimum Bandwidth could be
used to make sure that some minimum level of throughput is always available to service this
application. Alternatively, some small level of Guaranteed Minimum Bandwidth could be applied
to the other priority queues to make sure that other applications on the network will not be
starved (any leftover bandwidth after servicing the minimums is always given away on demand
If multiple VLANs to a server are done using 802.1Q, the server must also support 802.1Q tagging.


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