Cisco Catalyst 4500 Series, Software Configuration Manual

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Catalyst 4500 Series Switch, Cisco IOS Software Configuration Guide - Cisco IOS XE 3.9.xE and IOS 15.2(5)Ex
Chapter 1 Product Overview
Layer 3 Software Features
For details on Cisco IOS ISSU, refer to Chapter 7, “Configuring the Cisco IOS In-Service Software
Upgrade Process.”
For details on Cisco IOS XE ISSU, refer to Chapter 8, “Configuring the Cisco IOS XE In Service
Software Upgrade Process.”
IPv6
IPv6 provides services such as end-to-end security, quality of service (QoS), and globally unique
addresses. The IPv6 address space reduces the need for private addresses and Network Address
Translation (NAT) processing by border routers at network edges.
For more information about IPv6 services supported on a Catalyst 4500 series switch, see Chapter 63,
“Support for IPv6.”
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:
• ANCP Client —ANCP Multicast enables you to control multicast traffic on a Catalyst 4500 switch
using either ANCP (rather than IGMP) or direct static configuration on the CLI.
•
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.
The IGMP Snooping Querier is a Layer 2 feature required to support IGMP snooping in a VLAN
where PIM and IGMP are not configured because the multicast traffic does not require routing.
For information on configuring IGMP snooping, see Chapter 28, “Configuring IGMP Snooping and
Filtering, and MVR.”
•
IPv6 Multicast Listen Discovery (MLD) and Multicast Listen Discovery snooping—MLD is a
protocol used by IPv6 multicast devices to discover the presence of multicast listeners (nodes that
want to receive IPv6 multicast packets) on its directly attached links and to discover which multicast
packets are of interest to neighboring nodes. MLD snooping is supported in two different versions:
MLD v1 and MLD v2. Network switches use MLD snooping to limit the flood of multicast traffic,
causing IPv6 multicast data to be selectively forwarded to a list of ports that want to receive the data,
instead of being flooded to all ports in a VLAN. This lessens the load on devices in the network,
minimizing unnecessary bandwidth on links, enabling efficient distribution of IPv6 multicast data.
For information on configuring multicast services, see Chapter 29, “Configuring IPv6 Multicast
Listener Discovery Snooping.”