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The following are the prerequisites for configuring source-specific multicast (SSM) and SSM mapping:
Note | You can use a product such as Cisco Network Registrar to add records to a running DNS server. |
Information About SSM and SSM Mapping
SSM is a datagram delivery model that best supports one-to-many applications, also known as broadcast applications. It is an extension of IP multicast in which datagram traffic is forwarded to receivers from only those multicast sources that the receivers have explicitly joined. For multicast groups configured for SSM, only SSM distribution trees (no shared trees) are created.
SSM is a core networking technology for Cisco's implementation of IP multicast solutions targeted for audio and video broadcast application environments and is described in RFC 3569. The following components together support the implementation of SSM:
Protocol Independent Multicast (PIM) SSM, or PIM-SSM, is the routing protocol that supports the implementation of SSM and is derived from PIM sparse mode (PIM-SM). IGMP is the Internet Engineering Task Force (IETF) standards track protocol used for hosts to signal multicast group membership to routers. IGMP Version 3 supports source filtering, which is required for SSM. IGMP For SSM to run with IGMPv3, SSM must be supported in the router, the host where the application is running, and the application itself.
The standard IP multicast infrastructure in the Internet and many enterprise intranets is based on the PIM-SM protocol and Multicast Source Discovery Protocol (MSDP). These protocols have proved to be reliable, extensive, and efficient. However, they are bound to the complexity and functionality limitations of the Internet Standard Multicast (ISM) service model. For example, with ISM, the network must maintain knowledge about which hosts in the network are actively sending multicast traffic. With SSM, this information is provided by receivers through the source addresses relayed to the last-hop devices by IGMPv3. SSM is an incremental response to the issues associated with ISM and is intended to coexist in the network with the protocols developed for ISM. In general, SSM provides IP multicast service for applications that utilize SSM.
ISM service is described in RFC 1112. This service consists of the delivery of IP datagrams from any source to a group of receivers called the multicast host group. The datagram traffic for the multicast host group consists of datagrams with an arbitrary IP unicast source address S and the multicast group address G as the IP destination address. Systems will receive this traffic by becoming members of the host group. Membership in a host group simply requires signaling the host group through IGMP Version 1, 2, or 3.
In SSM, delivery of datagrams is based on (S, G) channels. Traffic for one (S, G) channel consists of datagrams with an IP unicast source address S and the multicast group address G as the IP destination address. Systems will receive this traffic by becoming members of the (S, G) channel. In both SSM and ISM, no signaling is required to become a source. However, in SSM, receivers must subscribe or unsubscribe to (S, G) channels to receive or not receive traffic from specific sources. In other words, receivers can receive traffic only from (S, G) channels to which they are subscribed, whereas in ISM, receivers need not know the IP addresses of sources from which they receive their traffic. The proposed standard approach for channel subscription signaling utilizes IGMP INCLUDE mode membership reports, which are supported only in IGMP Version 3.
SSM can coexist with the ISM service by applying the SSM delivery model to a configured subset of the IP multicast group address range. The Internet Assigned Numbers Authority (IANA) has reserved the address range from 232.0.0.0 through 232.255.255.255 for SSM applications and protocols. The software allows SSM configuration for an arbitrary subset of the IP multicast address range from 224.0.0.0 through 239.255.255.255. When an SSM range is defined, an existing IP multicast receiver application will not receive any traffic when it tries to use addresses in the SSM range unless the application is modified to use explicit (S, G) channel subscription or is SSM-enabled through a URL Rendezvous Directory (URD).
An established network in which IP multicast service is based on PIM-SM can support SSM services. SSM can also be deployed alone in a network without the full range of protocols that are required for interdomain PIM-SM. That is, SSM does not require an RP, so there is no need for an RP mechanism such as Auto-RP, MSDP, or bootstrap router (BSR).
If SSM is deployed in a network that is already configured for PIM-SM, then only the last-hop routers must be upgraded to a software image that supports SSM. Routers that are not directly connected to receivers do not have to upgrade to a software image that supports SSM. In general, these non-last-hop routers must only run PIM-SM in the SSM range. They may need additional access control configuration to suppress MSDP signaling, registering, or PIM-SM shared-tree operations from occurring within the SSM range.
The SSM mode of operation is enabled by configuring the SSM range using the ip pim ssm global configuration command. This configuration has the following effects:
IGMPv3 is the third version of the IETF standards track protocol in which hosts signal membership to last-hop routers of multicast groups. IGMPv3 introduces the ability for hosts to signal group membership that allows filtering capabilities with respect to sources. A host can signal either that it wants to receive traffic from all sources sending to a group except for some specific sources (a mode called EXCLUDE) or that it wants to receive traffic only from some specific sources sending to the group (a mode called INCLUDE).
IGMPv3 can operate with both ISM and SSM. In ISM, both EXCLUDE and INCLUDE mode reports are accepted by the last-hop router. In SSM, only INCLUDE mode reports are accepted by the last-hop router.
In the ISM service, applications must acquire a unique IP multicast group address because traffic distribution is based only on the IP multicast group address used. If two applications with different sources and receivers use the same IP multicast group address, then receivers of both applications will receive traffic from the senders of both applications. Even though the receivers, if programmed appropriately, can filter out the unwanted traffic, this situation would cause generally unacceptable levels of unwanted traffic.
Allocating a unique IP multicast group address for an application is still a problem. Most short-lived applications use mechanisms like Session Description Protocol (SDP) and Session Announcement Protocol (SAP) to get a random address, a solution that does not work well with a rising number of applications in the Internet. The best current solution for long-lived applications is described in RFC 2770, but this solution suffers from the restriction that each autonomous system is limited to only 255 usable IP multicast addresses.
In SSM, traffic from each source is forwarded between routers in the network independent of traffic from other sources. Thus different sources can reuse multicast group addresses in the SSM range.
In SSM, multicast traffic from each individual source will be transported across the network only if it was requested (through IGMPv3, IGMP v3lite, or URD memberships) from a receiver. In contrast, ISM forwards traffic from any active source sending to a multicast group to all receivers requesting that multicast group. In Internet broadcast applications, this ISM behavior is highly undesirable because it allows unwanted sources to easily disturb the actual Internet broadcast source by simply sending traffic to the same multicast group. This situation depletes bandwidth at the receiver side with unwanted traffic and thus disrupts the undisturbed reception of the Internet broadcast. In SSM, this type of denial of service (DoS) attack cannot be made by simply sending traffic to a multicast group.
SSM is easy to install and provision in a network because it does not require the network to maintain which active sources are sending to multicast groups. This requirement exists in ISM (with IGMPv1, IGMPv2, or IGMPv3).
The current standard solutions for ISM service are PIM-SM and MSDP. Rendezvous point (RP) management in PIM-SM (including the necessity for Auto-RP or BSR) and MSDP is required only for the network to learn about active sources. This management is not necessary in SSM, which makes SSM easier than ISM to install and manage, and therefore easier than ISM to operationally scale in deployment. Another factor that contributes to the ease of installation of SSM is the fact that it can leverage preexisting PIM-SM networks and requires only the upgrade of last hop routers to support IGMPv3, IGMP v3lite, or URD.
The three benefits previously described make SSM ideal for Internet broadcast-style applications for the following reasons:
SSM mapping supports SSM transition when supporting SSM on the end system is impossible or unwanted due to administrative or technical reasons. Using SSM to deliver live streaming video to legacy STBs that do not support IGMPv3 or for applications that do not use the IGMPv3 host stack is a typical application of SSM mapping.
In a typical STB deployment, each TV channel uses one separate IP multicast group and has one active server host sending the TV channel. A single server may of course send multiple TV channels, but each to a different group. In this network environment, if a router receives an IGMPv1 or IGMPv2 membership report for a particular group G, the report implicitly addresses the well-known TV server for the TV channel associated with the multicast group.
SSM mapping introduces a means for the last hop router to discover sources sending to groups. When SSM mapping is configured, if a router receives an IGMPv1 or IGMPv2 membership report for a particular group G, the router translates this report into one or more (S, G) channel memberships for the well-known sources associated with this group.
Note |
When the router receives an IGMPv1 or IGMPv2 membership report for group G, the router uses SSM mapping to determine one or more source IP addresses for group G. SSM mapping then translates the membership report as an IGMPv3 report INCLUDE (G, [S1, G], [S2, G]...[Sn, G] and continues as if it had received an IGMPv3 report. The router then sends out PIM joins toward (S1, G) to (Sn, G) and continues to be joined to these groups as long as it continues to receive the IGMPv1 or IGMPv2 membership reports and as long as it continues to receive the IGMPv1 or IGMPv2 membership reports, and the SSM mapping for the group remains the same. SSM mapping, thus, enables you to leverage SSM for video delivery to legacy STBs that do not support IGMPv3 or for applications that do not take advantage of the IGMPv3 host stack.
SSM mapping enables the last hop router to determine the source addresses either by a statically configured table on the router or by consulting a DNS server. When the statically configured table is changed, or when the DNS mapping changes, the router will leave the current sources associated with the joined groups.
SSM static mapping enables you to configure the last hop router to use a static map to determine the sources sending to groups. Static SSM mapping requires that you configure access lists (ACLs) to define group ranges. The groups permitted by those ACLs then can be mapped to sources using the ip igmp static ssm-map global configuration command.
You can configure static SSM mapping in smaller networks when a DNS is not needed or to locally override DNS mappings that may be temporarily incorrect. When configured, static SSM mappings take precedence over DNS mappings.
DNS-based SSM mapping enables you to configure the last hop router to perform a reverse DNS lookup to determine sources sending to groups (see the figure below). When DNS-based SSM mapping is configured, the router constructs a domain name that includes the group address G and performs a reverse lookup into the DNS. The router looks up IP address resource records (IP A RRs) to be returned for this constructed domain name and uses the returned IP addresses as the source addresses associated with this group. SSM mapping supports up to 20 sources for each group. The router joins all sources configured for a group.
The SSM mapping mechanism that enables the last hop router to join multiple sources for a group can be used to provide source redundancy for a TV broadcast. In this context, the redundancy is provided by the last hop router using SSM mapping to join two video sources simultaneously for the same TV channel. However, to prevent the last hop router from duplicating the video traffic, it is necessary that the video sources utilize a server-side switchover mechanism where one video source is active while the other backup video source is passive. The passive source waits until an active source failure is detected before sending the video traffic for the TV channel. The server-side switchover mechanism, thus, ensures that only one of the servers is actively sending the video traffic for the TV channel.
To look up one or more source addresses for a group G that includes G1, G2, G3, and G4, the following DNS resource records (RRs) must be configured on the DNS server:
G4.G3.G2.G1 [multicast-domain] [timeout] |
IN A source-address-1 |
|
IN A source-address-2 |
|
IN A source-address-n |
The multicast-domain argument is a configurable DNS prefix. The default DNS prefix is in-addr.arpa. You should only use the default prefix when your installation is either separate from the internet or if the group names that you map are global scope group addresses (RFC 2770 type addresses that you configure for SSM) that you own.
The timeout argument configures the length of time for which the router performing SSM mapping will cache the DNS lookup. This argument is optional and defaults to the timeout of the zone in which this entry is configured. The timeout indicates how long the router will keep the current mapping before querying the DNS server for this group. The timeout is derived from the cache time of the DNS RR entry and can be configured for each group/source entry on the DNS server. You can configure this time for larger values if you want to minimize the number of DNS queries generated by the router. Configure this time for a low value if you want to be able to quickly update all routers with new source addresses.
Note | Refer to your DNS server documentation for more information about configuring DNS RRs. |
To configure DNS-based SSM mapping in the software, you must configure a few global commands but no per-channel specific configuration is needed. There is no change to the configuration for SSM mapping if additional channels are added. When DNS-based SSM mapping is configured, the mappings are handled entirely by one or more DNS servers. All DNS techniques for configuration and redundancy management can be applied to the entries needed for DNS-based SSM mapping.
How to Configure SSM and SSM Mapping
Follow these steps to configure SSM:
If you want to use an access list to define the Source Specific Multicast (SSM) range, configure the access list before you reference the access list in the ip pim ssm command.
1.
enable
3.
ip pim ssm [default |
range
access-list]
5.
ip pim {sparse-mode |
sparse-dense-mode}
9.
copy running-config
startup-config
Command or Action | Purpose | |
---|---|---|
Step 1 |
enable
Example:
Switch> enable
|
Enables privileged EXEC mode. Enter your password if prompted. |
Step 2 | configure
terminal
Example: Switch# configure terminal | |
Step 3 | ip pim ssm [default |
range
access-list]
Example: Switch(config)# ip pim ssm range 20 | |
Step 4 | interface
type number
Example: Switch(config)# interface gigabitethernet 1/0/1 |
Selects an interface that is connected to hosts on which IGMPv3 can be enabled, and enters the interface configuration mode. The specified interface must be one of the following:
|
Step 5 | ip pim {sparse-mode |
sparse-dense-mode}
Example: Switch(config-if)# ip pim sparse-dense-mode |
Enables PIM on an interface. You must use either sparse mode or sparse-dense mode. |
Step 6 | ip igmp version
3
Example: Switch(config-if)# ip igmp version 3 |
Enables IGMPv3 on this interface. The default version of IGMP is set to Version 2. |
Step 7 | end
Example: Switch(config)# end | |
Step 8 | show running-config
Example: Switch# show running-config | |
Step 9 | copy running-config
startup-config
Example:
Switch# copy running-config startup-config
|
(Optional) Saves your entries in the configuration file. |
Configuring SSM Mapping
Follow these steps to configure static SSM Mapping:
1.
enable
3.
ip
igmp
ssm-map
enable
4.
no
ip
igmp
ssm-map
query
dns
5.
ip
igmp
ssm-map
static
access-list
source-address
8.
copy running-config
startup-config
Perform this task to configure the last hop router to perform DNS lookups to learn the IP addresses of sources sending to a group.
1.
enable
2.
configure
terminal
3.
ip
igmp
ssm-map
enable
4.
ip
igmp
ssm-map
query
dns
5.
ip
domain
multicast
domain-prefix
6.
ip
name-server
server-address1
[server-address2...server-address6]
7. Repeat Step Step 6 to configure additional DNS servers for redundancy, if required.
8.
end
10.
copy running-config
startup-config
Command or Action | Purpose | |||
---|---|---|---|---|
Step 1 |
enable
Example:
Switch> enable
|
Enables privileged EXEC mode. Enter your password if prompted. | ||
Step 2 |
configure
terminal
Example:
Switch# configure terminal
|
Enters global configuration mode. | ||
Step 3 |
ip
igmp
ssm-map
enable
Example:
Switch(config)# ip igmp ssm-map enable
|
Enables SSM mapping for groups in a configured SSM range. | ||
Step 4 |
ip
igmp
ssm-map
query
dns
Example:
Switch(config)# ip igmp ssm-map query dns
|
(Optional) Enables DNS-based SSM mapping.
| ||
Step 5 |
ip
domain
multicast
domain-prefix
Example:
Switch(config)# ip domain multicast ssm-map.cisco.com
|
(Optional) Changes the domain prefix used for DNS-based SSM mapping. | ||
Step 6 |
ip
name-server
server-address1
[server-address2...server-address6]
Example:
Switch(config)# ip name-server 10.48.81.21
|
Specifies the address of one or more name servers to use for name and address resolution. | ||
Step 7 | Repeat Step Step 6 to configure additional DNS servers for redundancy, if required. |
-- | ||
Step 8 |
end
Example:
Switch(config-if)# end
|
Returns to privileged EXEC mode. | ||
Step 9 | show running-config
Example: Switch# show running-config | |||
Step 10 | copy running-config
startup-config
Example:
Switch# copy running-config startup-config
|
(Optional) Saves your entries in the configuration file. |
Follow these steps to configure static traffic forwarding with SSM mapping on the last hop router:
1.
enable
4.
ip igmp
static-group
group-address
source ssm-map
7.
copy running-config
startup-config
Command or Action | Purpose | |||
---|---|---|---|---|
Step 1 |
enable
Example:
Switch> enable
|
Enables privileged EXEC mode. Enter your password if prompted. | ||
Step 2 | configure
terminal
Example: Switch# configure terminal | |||
Step 3 | interface
interface-id
Example: Switch(config)# interface gigabitethernet 1/0/1 |
Selects an interface on which to statically forward traffic for a multicast group using SSM mapping, and enters interface configuration mode. The specified interface must be one of the following:
These interfaces must have IP addresses assigned to them.
| ||
Step 4 | ip igmp
static-group
group-address
source ssm-map
Example: Switch(config-if)# ip igmp static-group 239.1.2.1 source ssm-map |
Configures SSM mapping to statically forward a (S, G) channel from the interface. Use this command if you want to statically forward SSM traffic for certain groups. Use DNS-based SSM mapping to determine the source addresses of the channels. | ||
Step 5 | end
Example: Switch(config)# end | |||
Step 6 | show running-config
Example: Switch# show running-config | |||
Step 7 | copy running-config
startup-config
Example:
Switch# copy running-config startup-config
|
(Optional) Saves your entries in the configuration file. |
Follow these steps to verify SSM mapping configuration and operation:
1.
enable
2.
show
ip
igmp
ssm-mapping
3.
show
ip
igmp
ssm-mapping
group-address
4.
show
ip
igmp
groups
[group-name |
group-address |
interface-type
interface-number]
[detail]
5.
show
host
6.
debug
ip
igmp
group-address
Command or Action | Purpose | |
---|---|---|
Step 1 |
enable
Example:
Switch> enable
|
Enables privileged EXEC mode. Enter your password if prompted. |
Step 2 |
show
ip
igmp
ssm-mapping
Example:
Switch# show ip igmp ssm-mapping
SSM Mapping : Enabled
DNS Lookup : Enabled
Mcast domain : ssm-map.cisco.com
Name servers : 10.0.0.3
10.0.0.4
|
(Optional) Displays information about SSM mapping configuration. |
Step 3 |
show
ip
igmp
ssm-mapping
group-address
Example:
Switch# show ip igmp ssm-mapping 232.1.1.4
Group address: 232.1.1.4
Database : DNS
DNS name : 4.1.1.232.ssm-map.cisco.com
Expire time : 860000
Source list : 172.16.8.5
: 172.16.8.6
|
(Optional) Displays the sources that SSM mapping uses for a particular group. The example here shows information about the configured DNS-based SSM mapping. Here the router has used DNS-based mapping to map group 232.1.1.4 to sources 172.16.8.5 and 172.16.8.6. The timeout for this entry is 860000 milliseconds (860 seconds). |
Step 4 |
show
ip
igmp
groups
[group-name |
group-address |
interface-type
interface-number]
[detail]
Example:
Switch# show ip igmp group 232.1.1.4 detail
Interface: GigabitEthernet2/0/0
Group: 232.1.1.4 SSM
Uptime: 00:03:20
Group mode: INCLUDE
Last reporter: 0.0.0.0
CSR Grp Exp: 00:02:59
Group source list: (C - Cisco Src Report, U - URD, R - Remote,
S - Static, M - SSM Mapping)
Source Address Uptime v3 Exp CSR Exp Fwd Flags
172.16.8.3 00:03:20 stopped 00:02:59 Yes CM
172.16.8.4 00:03:20 stopped 00:02:59 Yes CM
172.16.8.5 00:03:20 stopped 00:02:59 Yes CM
172.16.8.6 00:03:20 stopped 00:02:59 Yes CM
|
(Optional) Displays the multicast groups with receivers that are directly connected to the router and that were learned through IGMP. In the example the “M” flag indicates that SSM mapping is configured. |
Step 5 |
show
host
Example:
Switch# show host
Default domain is cisco.com
Name/address lookup uses domain service
Name servers are 10.48.81.21
Codes: UN - unknown, EX - expired, OK - OK, ?? - revalidate
temp - temporary, perm - permanent
NA - Not Applicable None - Not defined
Host Port Flags Age Type Address(es)
10.0.0.0.ssm-map.cisco.c None (temp, OK) 0 IP 172.16.8.5
172.16.8.6
172.16.8.3
|
(Optional) Displays the default domain name, the style of name lookup service, a list of name server hosts, and the cached list of hostnames and addresses. |
Step 6 |
debug
ip
igmp
group-address
Example: Switch# debug ip igmp
IGMP(0): Convert IGMPv2 report (*,232.1.2.3) to IGMPv3 with 2 source(s) using STATIC.
Switch# debug ip igmp
IGMP(0): Convert IGMPv2 report (*,232.1.2.3) to IGMPv3 with 2 source(s) using DNS.
Switch# debug ip igmp
IGMP(0): DNS source lookup failed for (*, 232.1.2.3), IGMPv2 report failed
|
(Optional) Displays the IGMP packets received and sent and IGMP host-related events. In the first example, the output indicates that the router is converting an IGMPv2 join for group G into an IGMPv3 join. In the second example, the output indicates that a DNS lookup has succeeded. In the third example, the output indicates that DNS-based SSM mapping is enabled and a DNS lookup has failed: |
Monitoring SSM and SSM Mapping
To monitor SSM, use the following commands in privileged EXEC mode, as needed:
Command |
Purpose |
---|---|
Switch# show ip igmp groups detail |
Displays the (S, G) channel subscription through IGMPv3. |
Switch# show ip mroute |
Displays whether a multicast group supports SSM service or whether a source-specific host report was received. |
Command |
Purpose |
---|---|
Displays the sources that SSM mapping uses for a particular group. |
|
Switch#show ip igmp groups [group-name | group-address | interface-type interface-number] [detail] |
Displays the multicast groups with receivers that are directly connected to the router and that were learned through IGMP. |
Displays the default domain name, the style of name lookup service, a list of name server hosts, and the cached list of hostnames and addresses. |
|
Displays the IGMP packets received and sent and IGMP host-related events. |
Configuration Examples for SSM and SSM Mapping
The following example shows how to configure a device (running IGMPv3) for SSM:
ip multicast-routing ! interface GigabitEthernet3/1/0 ip address 172.21.200.203 255.255.255.0 description backbone interface ip pim sparse-mode ! interface GigabitEthernet3/2/0 ip address 131.108.1.2 255.255.255.0 ip pim sparse-mode description ethernet connected to hosts ip igmp version 3 ! ip pim ssm default
The following example shows how to configure filtering on legacy RP routers running software releases that do not support SSM routing. This filtering will suppress all unwanted PIM-SM and MSDP traffic in the SSM range. Without this filtering, SSM will still operate, but there may be additional RPT traffic if legacy first hop and last hop routers exist in the network.
ip access-list extended no-ssm-range deny ip any 232.0.0.0 0.255.255.255 ! SSM range permit ip any any ! Deny registering in SSM range ip pim accept-register list no-ssm-range ip access-list extended msdp-nono-list deny ip any 232.0.0.0 0.255.255.255 ! SSM Range ! . ! . ! . ! See ftp://ftpeng.cisco.com/ipmulticast/config-notes/msdp-sa-filter.txt for other SA ! messages that typically need to be filtered. permit ip any any ! Filter generated SA messages in SSM range. This configuration is only needed if there ! are directly connected sources to this router. The “ip pim accept-register” command ! filters remote sources. ip msdp redistribute list msdp-nono-list ! Filter received SA messages in SSM range. “Filtered on receipt” means messages are ! neither processed or forwarded. Needs to be configured for each MSDP peer. ip msdp sa-filter in msdp-peer1 list msdp-nono-list ! . ! . ! . ip msdp sa-filter in msdp-peerN list msdp-nono-list
The following configuration example shows a router configuration for SSM mapping. This example also displays a range of other IGMP and SSM configuration options to show compatibility between features. Do not use this configuration example as a model unless you understand all of the features used in the example.
Note | Address assignment in the global SSM range 232.0.0.0/8 should be random. If you copy parts or all of this sample configuration, make sure to select a random address range but not 232.1.1.x as shown in this example. Using a random address range minimizes the possibility of address collision and may prevent conflicts when other SSM content is imported while SSM mapping is used. |
! no ip domain lookup ip domain multicast ssm.map.cisco.com ip name-server 10.48.81.21 ! ! ip multicast-routing distributed ip igmp ssm-map enable ip igmp ssm-map static 10 172.16.8.10 ip igmp ssm-map static 11 172.16.8.11 ! ! . . . ! interface GigabitEthernet0/0/0 description Sample IGMP Interface Configuration for SSM-Mapping Example ip address 10.20.1.2 255.0.0.0 ip pim sparse-mode ip igmp last-member-query-interval 100 ip igmp static-group 232.1.2.1 source ssm-map ip igmp version 3 ip igmp explicit-tracking ip igmp limit 2 ip igmp v3lite ip urd ! . . . ! ip pim ssm default ! access-list 10 permit 232.1.2.10 access-list 11 permit 232.1.2.0 0.0.0.255 !
This table describes the significant commands shown in the SSM mapping configuration example.
Command |
Description |
||
---|---|---|---|
no ip domain lookup |
Disables IP DNS-based hostname-to-address translation.
|
||
ip domain multicast ssm-map.cisco.com |
Specifies ssm-map.cisco.com as the domain prefix for SSM mapping. |
||
ip name-server 10.48.81.21 |
Specifies 10.48.81.21 as the IP address of the DNS server to be used by SSM mapping and any other service in the software that utilizes DNS. |
||
ip multicast-routing |
Enables IP multicast routing. |
||
ip igmp ssm-map enable |
Enables SSM mapping. |
||
ip igmp ssm-map static 10 172.16.8.10 |
Configures the groups permitted by ACL 10 to use source address 172.16.8.10. |
||
ip igmp ssm-map static 11 172.16.8.11
|
Configures the groups permitted by ACL 11 to use source address 172.16.8.11. |
||
ip pim sparse-mode |
Enables PIM sparse mode. |
||
ip igmp last-member-query-interval 100 |
Reduces the leave latency for IGMPv2 hosts.
|
||
ip igmp static-group 232.1.2.1 source ssm-map
|
Configures SSM mapping to be used to determine the sources associated with group 232.1.2.1. The resulting (S, G) channels are statically forwarded. |
||
ip igmp version 3 |
Enables IGMPv3 on this interface.
|
||
ip igmp explicit-tracking |
Minimizes the leave latency for IGMPv3 host leaving a multicast channel.
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ip igmp limit 2 |
Limits the number of IGMP states resulting from IGMP membership states on a per-interface basis.
|
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ip igmp v3lite |
Enables the acceptance and processing of IGMP v3lite membership reports on this interface.
|
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ip urd |
Enables interception of TCP packets sent to the reserved URD port 465 on an interface and processing of URD channel subscription reports.
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ip pim ssm default |
Configures SSM service. |
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access-list 10 permit 232.1.2.10 access-list 11 permit 232.1.2.0 0.0.0.255 |
Configures the ACLs to be used for static SSM mapping.
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To configure DNS-based SSM mapping, you need to create a DNS server zone or add records to an existing zone. If the routers that are using DNS-based SSM mapping are also using DNS for other purposes besides SSM mapping, you should use a normally-configured DNS server. If DNS-based SSM mapping is the only DNS implementation being used on the router, you can configure a fake DNS setup with an empty root zone, or a root zone that points back to itself.
The following example shows how to create a zone and import the zone data using Network Registrar:
Router> zone 1.1.232.ssm-map.cisco.com. create primary file=named.ssm-map 100 Ok Router> dns reload 100 Ok
The following example shows how to import the zone files from a named.conf file for BIND 8:
Router> ::import named.conf /etc/named.conf Router> dns reload 100 Ok:
Note | Network Registrar version 8.0 and later support import BIND 8 format definitions. |
Related Topic | Document Title |
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For complete syntax and usage information for the commands used in this chapter. |
Command Reference, Cisco Release 15.2(2)E (Industrial Ethernet 3000 Switch) |
Cisco IOS commands |
Description | Link |
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To help you research and resolve system error messages in this release, use the Error Message Decoder tool. |
https://www.cisco.com/cgi-bin/Support/Errordecoder/index.cgi |
Standard/RFC | Title |
---|---|
RFC 4601 |
Protocol-Independent Multicast-Sparse Mode (PIM-SM): Protocol Specification |
MIB | MIBs Link |
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All supported MIBs for this release. |
To locate and download MIBs for selected platforms, Cisco IOS releases, and feature sets, use Cisco MIB Locator found at the following URL: |
Description | Link |
---|---|
The Cisco Support website provides extensive online resources, including documentation and tools for troubleshooting and resolving technical issues with Cisco products and technologies. To receive security and technical information about your products, you can subscribe to various services, such as the Product Alert Tool (accessed from Field Notices), the Cisco Technical Services Newsletter, and Really Simple Syndication (RSS) Feeds. Access to most tools on the Cisco Support website requires a Cisco.com user ID and password. |