Dynamic multicast routing

Depending on its position in the multicast infrastructure, the firewall may be identified as a:

  • First Hop Router (FHR): the firewall is connected to a multicast source and sends its multicast traffic to the RP (PIM-SM) or to the destination (PIM-SSM).
  • Middle Hop Router (MHR): the firewall acts as an intermediary and forwards multicast traffic.
  • Last Hop Router (LHR): the firewall is connected to multicast receivers and sends subscription/unsubscription requests from these receivers to the RP.

The information shown in the grids described below vary according to the position of the firewall in a given multicast traffic stream.

The firewall may also be required to play specific roles in the multicast infrastructure:

  • Rendez-vous Point (RP): the RP is contacted to set up the route up to the multicast source (upstream), then to transfer received transfer to receivers (downstream).
  • BootStrap router) (BSR): the BSR is elected out of the pool of BSR candidates. Once it is elected, it will gather candidacies for the role of RP, then shares the table of multicast group/RP associations with other routers.

For more information on these roles and election mechanisms, refer to the configuration module in Dynamic multicast routing.

Possible actions

  •  : click on this button to refresh the data displayed in the dynamic multicast routing monitoring grids.
  •  : click on this button to change the frequency (in seconds) with which data displayed in the dynamic multicast routing monitoring grids is refreshed. The default value is 30 days.
  •  : click on this button to collapse all the monitoring grids shown on the screen.
  • : click on this button to expand all the monitoring grids shown on the screen.
  • : click on this button to directly access the dynamic multicast routing configuration module (Configuration > Network > Multicast routing).

Grids

Multicast routes

This grid shows the multicast routing table that the firewall has learned. The firewall does not necessarily use all routes listed in this grid.

Source

This field indicates the IP address or host object that represents the address of the source of the multicast traffic for the route shown.

The value of this source is specified when the firewall meets one of the following conditions:

  • It is the FHR from the source,
  • It has been elected as RP (PIM-SM),
  • It is placed on the route of the Shortest Path Tree (SPT) when this route is set up.

The any value appears when the firewall meets one of the following conditions:

  • It is the RP for the multicast group, and it is informed of subscription requests,
  • It is the LHR of a receiver (PIM-SM),
  • It is placed on the route between the LHR and RP.
Group Indicates the IP address or host object that represents the IP address of the multicast group to which the route applies.
RP address

PIM-SM protocol :

Specifies the IP address or host object that represents the IP address of the RP that manages this multicast route. This name is shown in bold when the monitored router itself has been elected as the RP of the selected multicast route.

PIM-SSM protocol :

No address is entered because the RP role does not exist in this protocol.

Flags

There are several possible values:

  • SG: when the source has been identified for the multicast route,
  • CACHE: when the route has been enabled on the monitored firewall,
  • SPT (only in PIM-SM):
    • When the firewall is the RP, this flag then indicates that the SPT is available,
    • When the firewall is positioned as the LHR: this flag indicates that the traffic passes through the SPT,
  • WC-RPT: when the firewall is positioned on the route of the LHR (inclusive) on the way to the RP (inclusive),
  • ASSERTED: when the firewall gains the PIM assert mechanism, which makes it possible to eliminate traffic duplicates over a shared segment.

Do note that these various values can be combined with one another.

Details

By scrolling over this section, you will see the ongoing timeouts for the mechanisms that run in the PIM SM protocol.

The timeouts shown (route expiry [expiry timer], end of a traffic transmission when there are no more declared receivers [register suppression], etc.) depend on the firewall's position in the multicast infrastructure (first hop, middle hop or last hop), and on its role(s) (RP and/or BSR).

RFC 4601 sets out details of these timeouts.

Click on the "+" in a multicast route to obtain further details:

Interface This column lists the interfaces that are part of the selected multicast route.
Incoming(IIF) For a given multicast route, the interface that has a check is the interface through which multicast traffic arrives on the firewall.
Outgoing interface list (OIL)
  • Joined: a check indicates that this interface has been used for a multicast subscription request.
  • Pruned: a check indicates that this interface has been used for a multicast unsubscription request.
  • Leaf: a check indicates that this interface has been directly connected to a receiver.
  • Asserted: a check indicates that this interface was used in the PIM assert mechanism.
  • Outgoing: a check indicates that this interface has been used to forward multicast traffic.

IGMP group members

NOTE
Information appears in this grid only when the firewall is positioned as the last hop router in a multicast traffic stream.

By clicking on the title of a column, information in the grid can be sorted by the value in question.

Click on the "+" in a multicast group to obtain the list of receivers that make up the group.

Group Address or host object that represents the IP address of the group for which the IGMP request was initiated.
Source

Address or host object that represents the IP address of the source of the multicast traffic for the group in question.

Receiver Address or host object that represents the IP address of the IGMP request initiator.
Interface Shows the interface through which the firewall received the IGMP request.
Timeout When this value is reached, this means that the receiver in question no longer listens on the IGMP traffic.

Interfaces/Neighbors

This grid lists all the firewall interfaces that participate in multicast routing, as well as the neighbors of these interfaces. A neighbor is another network device (e.g., router or firewall) that uses the PIM protocol, and which is directly connected to the listed interface.

Some of the information is available only for interfaces, while other information is available for interfaces and their neighbors.

Interface/Neighbor

Shown only for the interface.

Name of the firewall interface that participates in multicast routing.

The number of neighbors that this interface has is shown in brackets.

Click on the interface's "+" symbol to see details about its neighbors.

Status

Shown only for the interface.

Indicates whether interface is enabled.

Group

Shown only for the interface.

Number of distinct multicast groups contacted by receivers that are connected to the interface.

Address

Shown for the interface and its neighbors.

Address or host object that represents the IP address of the interface or of its neighbor.

DR priority

Shown for the interface and its neighbors.

Indicates the priority assigned to the interface or to its neighbor as part of the DR election.

DR

Shown for the interface and its neighbors.

Indicates whether the interface or its neighbor has been elected as the DR.

When the check is followed by an asterisk, this means that it is an interface on the monitored router that was elected as the DR.

IGMP requester

Shown for the interface and its neighbors.

A check indicates that the interface or its neighbor acts as the IGMP requester, which has to contact receivers to find out whether they are still listening on certain multicast traffic streams.

Since Indicates the time lapsed since the discovery of the neighbor.
Expires in Remaining time before the neighbor disappears, if it has not sent any HELLO messages,

Rendez-vous Points (RP)/Candidates (C-RP)

NOTE
Data is shown in this grid only when the PIM SM protocol is used (the concept of RPs does not exist in the PIM SSM protocol).

Multicast group

Indicates the address or host/network object that represents the IP address of the multicast group managed by the RP.

When the associated RP is a dynamic RP, the number of RP election candidates is indicated in brackets.

RP > C-RP address

On a main line, this field indicates the address or host object that represents the IP address of the designated RP (static RP) or elected RP (dynamic RP) for the multicast group shown.

On a dynamic RP, clicking on the "+" displays the list of RP election candidates for the multicast group in question.

Type Indicates whether it is a static or dynamic (elected) RP.
Priority

Displays the priority assigned to the RP or candidate RP.

Hold-time Interval between two candidate RP advertisements to the BSR.
Expires in Expiry period of the candidature if the candidate no longer sends any advertisements to the BSR.

Neighboring bootstrap routers (BSR)/candidates (C-BSR)

NOTE
Data is shown in this grid only when the PIM SM protocol is used, as the concept of BSRs does not exist in the PIM SSM protocol.

BSR/C-BSR address References the address of the host object that represents the IP address of the BSR as well as the candidates (C-BSR) advertised by the firewall's neighbors.
Priority Shows the priority assigned to the C-BSR in the election.
Hash mask length

Shows the size (number of significant bits) used to balance multicast groups among DRs when there is an overlap.

The mask is set to 30 by default.

Expires in

This is the remaining time until the next election when the BSR is lost.

This value is shown only for the elected BSR.