DGS-3312SR Stackable Gigabit Layer 3 Switch
164
PIM
The
Protocol Independent Multicast - Dense Mode
(PIM-DM) protocol should be used in networks with a low delay (low
latency) and high bandwidth as PIM-DM is optimized to guarantee delivery of multicast packets, not to reduce overhead.
The PIM-DM multicast routing protocol is assumes that all downstream routers want to receive multicast messages and
relies upon explicit prune messages from downstream routers to remove branches from the multicast delivery tree that do
not contain multicast group members.
PIM-DM has no explicit ‘join’ messages. It relies upon periodic flooding of multicast messages to all interfaces and then
either waiting for a timer to expire (the
Join/Prune Interval
) or for the downstream routers to transmit explicit ‘prune’
messages indicating that there are no multicast members on their respective branches. PIM-DM then removes these
branches (‘prunes’ them) from the multicast delivery tree.
Because a member of a pruned branch of a multicast delivery tree may want to join a multicast delivery group (at some
point in the future), the protocol periodically removes the ‘prune’ information from its database and floods multicast
messages to all interfaces on that branch. The interval for removing ‘prune’ information is the
Join/Prune Interval
.
PIM-DM Global Setting
To use PIM-DM on the Switch it must be enabled globally. Use the
PIM-DM Global Setting
window to enable or disable
PIM-DM globally. Disabling PIM-DM will not affect any PIM-DM settings that have been configured so it can later be
enabled and apply the same settings. To enable PIM-DM globally on the Switch, go to
Configuration > Layer 3 IP
Networking > IP Multicast > PIM > PIM-DM Interface Settings
. This will give the user access to the following screen:
Figure 5- 54. PIM-DM Global Setting window
Select
Enabled
or
Disabled
and click on the
Apply
button to make the change.
PIM-DM Interface Settings
To view the
PIM-DM Interface Settings
, click
Configuration > Layer 3 IP Networking > IP Multicast > PIM > PIM-
DM Interface Settings.
This window allows the
PIM-DM
to be configured for each IP interface defined on the Switch.
Each IP interface configured on the Switch is displayed in the below
PIM-DM Interface Settings
dialog box. To
configure PIM-DM for a particular interface, click the corresponding hyperlink for that IP interface. This will open the
PIM-DM Interface Settings
window:
Figure 5- 55. PIM-DM Interface Settings window
PIM-DM settings can be configured on the Switch for existing IP interfaces. Each IP interface configured on the Switch is
displayed
in
the
PIM-DM Interface Settings
window. To configure an IP interface click on the hyperlinked
Interface
Name
: