Multicast Services; Network Security With Acls - Cisco 4500M Software Manual

Chapter 1 Product Overview

Multicast Services

Multicast services save bandwidth by forcing the network to replicate packets only when necessary and
by allowing hosts to join and leave groups dynamically. The following multicast services are supported:
•
•
•

Network Security with ACLs

An access control list (ACL) filters network traffic by controlling whether routed packets are forwarded
or blocked at the router interfaces. The Catalyst 4500 series switch examines each packet to determine
whether to forward or drop the packet based on the criteria you specified within the access lists.
MAC access control lists (MACLs) and VLAN access control lists (VACLs) are supported. VACLs are
also known as VLAN maps in Cisco IOS.
The following security features are supported:
•
•
For information on ACLs, MACLs, VLAN maps, MAC address filtering, and Port ACLs, see
Chapter 35, "Configuring Network Security with ACLs."
OL-6696-01
Cisco Group Management Protocol (CGMP) server—CGMP server manages multicast traffic.
Multicast traffic is forwarded only to ports with attached hosts that request the multicast traffic.
Internet Group Management Protocol (IGMP) snooping—IGMP snooping manages multicast
traffic. The switch software examines IP multicast packets and forwards packets based on their
content. Multicast traffic is forwarded only to ports with attached hosts that request multicast traffic.
Support for IGMPv3 provides constrained flooding of multicast traffic in the presence of IGMPv3
hosts or routers. IGMPv3 snooping listens to IGMPv3 query and membership report messages to
maintain host-to-multicast group associations. It enables a switch to propagate multicast data only
to ports that need it. IGMPv3 snooping is fully interoperable with IGMPv1 and IGMPv2.
Explicit Host Tracking (EHT) is an extension to IGMPv3 snooping. EHT enables immediate leave
operations on a per-port basis. EHT can be used to track per host membership information or to
gather statistics about all IGMPv3 group members.
For information on configuring IGMP snooping, see
Filtering."
Protocol Independent Multicast (PIM)—PIM is protocol-independent because it can leverage
whichever unicast routing protocol is used to populate the unicast routing table, including EIGRP,
OSPF, BGP, or static route. PIM also uses a unicast routing table to perform the Reverse Path
Forwarding (RPF) check function instead of building a completely independent multicast routing
table.
For information on configuring multicast services, see
IP Multicast."
MAC address filtering, which enables you to block unicast traffic for a MAC address on a VLAN
interface.
Port ACLs, which enable you to apply ACLs to Layer 2 interfaces on a switch for inbound traffic.
Chapter 18, "Configuring IGMP Snooping and
Chapter 25, "Understanding and Configuring
Software Configuration Guide—Release 12.2(25)EW
Layer 3 Software Features
1-9