All Cisco-Network Study Notes: Configuring Cisco Accumulation Management Agreement (CGMP)

Configuring Cisco Accumulation Management Agreement (CGMP)

Cisco Accumulation Management Agreement (CGMP) runs on Catalyst switches and Cisco routers.

CGMP is acclimated in affiliation with IGMP active on Cisco routers to actuate forwarding

information. CGMP letters are beatific to the acclaimed multicast MAC abode of 01-00-0cdd-

dd-dd. Catalyst switches ascertain CGMP routers via a accost mechanism.

CGMP is able of operating accurately alone back it is alive in affiliation with a router.

The router is bare to ascertain IGMP packets and acquaint with the CGMP-enabled switch.

The about-face receives CGMP packets created by the router.

NOTE CGMP is disabled by absence on the XDI interface of Cisco Catalyst switches.

This area covers the agreement of CGMP on a Cisco router and additionally on a Catalyst switch.

To configure CGMP on a Cisco router, admission the afterward command for a accurate interface:

DallasR1>(config-if)#ip cgmp

Upon hitting the Admission key, a CGMP Accompany bulletin is sent.

Example 11-6 demonstrates a router agreement with CGMP for a router (RouterLA1)

connected to a Catalyst about-face (CatalystLA1).

The command to attenuate CGMP is the aforementioned as any aural the Cisco IOS; that is, use no in front

of the antecedent command:

DallasR1>(config-if)#no ip cgmp

Disabling CGMP triggers a CGMP Leave bulletin agnate to the CGMP Accompany bulletin triggered

when enabling CGMP.

Example 11-6 Router Agreement with CGMP

RouterLA1>#show running-config

hostname RouterLA1>

ip multicast routing

interface FastEthernet 3/1.0

ip abode 192.168.3.15 255.255.255.0

ip pim dense-mode

ip cgmp

384 Affiliate 11: Configuring Multicast Networks

You additionally charge to configure the about-face in a multicast environment. Enabling CGMP on a

Catalyst about-face requires the afterward command in accredit mode:

DallasS1>(enable)set cgmp enable

Running appearance config on the Catalyst about-face reveals that CGMP is enabled as approved in

Example 11-7.

As is archetypal syntax on a Catalyst switch, entering the set cgmp attenuate command turns CGMP

off.

Configuring CGMP Leave

In some cases, you may appetite multicast accumulation to be removed from the forwarding tables, freeing

up bandwidth. The command to achieve this, alleged CGMP leave, is as follows:

Dallas_SW(enable)set cgmp leave

A multicast router sends out accumulation queries periodically. In a accustomed accommodating mode, the

multicast hosts would accelerate a acknowledgment to these queries. If, afterwards a accustomed cardinal of queries no

response is accustomed by any associates of a group, that accumulation is again acceptable to be pruned from the

forwarding tables of the switch.

Example 11-7 Verifying CGMP Agreement on a Catalyst Switch

CatalystLA1>(enable)show config

set alert CatalystLA1>

set interface sc0 192.168.1.1 255.255.255.0

set cgmp enable

Foundation Arbitrary 385

Foundation Summary

The Foundation Arbitrary is a accumulating of tables and abstracts that provides a acceptable review

of abounding key concepts in this chapter. For those of you already adequate with the capacity in

this chapter, this arbitrary could advice you anamnesis a few details. For those of you who aloof read

this chapter, this analysis should advice coalesce some key facts. For any of you accomplishing your final

prep afore the exam, these tables and abstracts will hopefully be a acceptable way to analysis the

day afore the exam.

Table 11-2 Multicast About-face Commands

Command Description

set cgmp accredit Enables CGMP processing on the switch

show cgmp Displays accepted CGMP settings

set cgmp leave Allows pruning of multicast groups

show config Displays the agreement of the switch

Table 11-3 Multicast Router Commands

Command Description

ip cgmp Enables abutment of CGMP

ip multicast-routing Enables IP multicast routing

ip pim sparse-dense-mode Enables the PIM agreement on an interface

ip pim rp-address Specifies an RP abode to accredit PIM dispersed mode

ip igmp join-group group-address Enables router to accompany IGMP group

show ip pim acquaintance Displays PIM neighbors

debug ip mpacket [detail] [access-list]

[group]

Enables debugging of multicast packets

show ip mroute Displays the capacity of the multicast acquisition table

show ip mroute host-ip group-ip Displays the capacity of the multicast acquisition table for a

specified IP host abode and defined IPmulticast address

show run Displays the accepted configuration

ip multicast ttl-threshold ttl-value Configures a TTL threshold

386 Affiliate 11: Configuring Multicast Networks

Q&A

The questions and scenarios in this book are added difficult than what you should acquaintance on

the absolute exam. The questions do not attack to awning added across or abyss than the exam;

however, they are advised to accomplish abiding that you apperceive the answer. Rather than acceptance you

to acquire the acknowledgment from clues hidden central the catechism itself, the questions claiming your

understanding and anamnesis of the subject. Questions from the “Do I Apperceive This Already?” quiz

from the alpha of the affiliate are again actuality to ensure that you accept baffled the

chapter’s affair areas. Hopefully, these questions will advice absolute the cardinal of assay questions

on which you attenuated your choices to two options and again guess.

The answers to these questions can be begin in Appendix A, on folio 477.

1 Which Internet Request for Comments (RFC) deals with multicasts?

______________________________________________________________________

2 What is the name of the industry accepted agreement that deals with multicast groups? The

Cisco proprietary protocol?

______________________________________________________________________

3 What command enables multicast acquisition on a Cisco router?

______________________________________________________________________

4 What command is issued to accredit PIM in Dispersed Mode?

______________________________________________________________________

5 What is the absence blazon of IGMP acclimated in a Cisco router?

______________________________________________________________________

Q&A 387

6 What command would you use to affectation all multicast packets accustomed and transmitted

on a router?

_______________________________________________________________________

7 What is the cachet of CGMP in absence approach on a Cisco router?

_______________________________________________________________________

8 How is CGMP enabled on a Cisco router? On a Catalyst switch?

_______________________________________________________________________

9 What is the purpose of CGMP leave?

_______________________________________________________________________

10 Name one multicast acquisition agreement that is acclimated by Cisco routers for router-to-router

communication?

_______________________________________________________________________

11 What is the MBONE? What multicast acquisition agreement is acclimated throughout the MBONE?

_______________________________________________________________________

12 What are the two basal tasks associated with configuring IP multicasts on a Cisco router?

_______________________________________________________________________

388 Affiliate 11: Configuring Multicast Networks

13 What action is acclimated aural PIM router-to-router advice that is additionally acclimated in an

OSPF arrangement over a multi-access network?

______________________________________________________________________

14 Name one of the three affidavit why an interface would be placed in the oilist for a

multicast group.

______________________________________________________________________

15 Define Rendezvous Point and actuate beneath what affairs Rendezvous Point

would be used.

______________________________________________________________________

16 What troubleshooting command can be acclimated to actuate which routers accord to an

IGMP group?

______________________________________________________________________

17 Assume that you accept a router called Router1 affiliated to added networks from a wide

area angle and a Catalyst about-face affiliated to Router1 on anchorage Ethernet 0. What

commands would be appropriate to accredit basal CGMP in this network?

______________________________________________________________________

18 What happens back a CGMP-enabled router receives an IGMP ascendancy packet?

______________________________________________________________________

Scenario 11-1 389

Scenarios

Scenario 11-1

In this scenario, depicted in Figure 11-4, we accept an IP alive video appliance being

downloaded from a accessory dish. The video server is demography the video stream, buffering it, and

converting it to a multicast application. From there the video beck is actuality beatific to two

different multicast groups. Accustomed this information, complete the tasks that chase to accomplish this

application work.

Figure 11-4 Book 11-1 Arrangement Setup

1 Configure IP Multicast abutment in the router.

2 Configure IP PIM in dispersed approach on the router.

3 Affectation PIM advice about interface VLAN10.

4 Affectation the PIM acquaintance tables.

5 Configure an RP with abode 172.16.1.2.

6 Configure CGMP on both the router and the switch.

Multicast Accumulation X Multicast Accumulation Y

390 Affiliate 11: Configuring Multicast Networks

Scenarios Answers

Scenario 11-1 Answers

1 To configure IP multicast on the router, admission the afterward command at the global

configuration prompt:

Router(config)#ip multicast-routing

2 To configure PIM in dispersed mode, admission the afterward command at the interface prompt:

Router (config-if)# ip pim sparse-mode

3 To affectation PIM advice about interface VLAN10, admission the afterward command at the

prompt:

Router#show ip pim interface

4 To affectation the PIM acquaintance tables, admission the afterward command at the prompt:

Router#show ip pim neighbor

5 To configure an RP, admission the afterward command while in all-around agreement mode:

Router>#ip pim rp-address 172.16.1.2

6 To configure CGMP on the router, admission the afterward command:

Router>#ip cgmp

CGMP is commonly disabled on a Cisco router. The agreement of a about-face is additionally very

simple. The agreement is as follows:

Switch>(enable)set cgmp enable

This affiliate covers the afterward capacity that you will charge to adept for the CCNP

Switching Exam:

• Admission Policies—This area discusses the charge for an admission policy. Admission policies

define who has admission to what.

• Managing Arrangement Devices—This area discusses the altered methods for

controlling and managing arrangement devices.

• Admission Band Policy—This area discusses the blazon of action bare at the access

layer of the about-face block.

• Distribution Band Policy—This area discusses the blazon of action bare at the

distribution band of the about-face block.

• Amount Band Policy—This area discusses the blazon of action bare at the amount layer

of the about-face block.