IOS Software for the Cisco Catalyst 4500 Series Supervisor Engines IV, V, and V-10GE (Enterprise Services image with BGP support)
<b>In-Service Software Upgrade</b>
In-Service Software Upgrade (ISSU) allows a customer to upgrade or downgrade complete IOS images with minimal to no impact on a Catalyst 4500 system with redundant supervisor engines. It enables rapid, non-disruptive software upgrades for new line cards, new power supplies, new features, or bug fixes. ISSU offers continuous packet forwarding during the supervisor engine switchover running different IOS software versions. Together with Nonstop Forwarding/Stateful Switchover (NSF/SSO), ISSU allows forwarding of data packets along known routes without any route flaps or network instabilities during the software upgrade. As a result, IP phone calls do not drop even when the IOS Software images are upgraded or downgraded. There is no impact to the overall network capacity since the switch and all the forwarding paths remain active during the entire upgrade process. ISSU is typically deployed in the enterprise wiring closet or service provider Metro Ethernet aggregation. ISSU eliminates planned downtime to maximize system and network availability.
The ISSU feature is available in both IP Base and Enterprise Service packages with dual supervisor engine configurations. A promotional ISSU license (FR45-ISSU-POE-LIC) is a selectable option with new factory-configured 4507R/4510R chassis that meet a minimum requirement of dual supervisors and at least 48 PoE ports. For new configurations that do not qualify for this promotion, and for all existing installed base chassis with dual supervisors, purchase of an ISSU feature license (FR45-ISSU-LIC) is required. (one per chassis). See Table 3 for more details.
<b>Trunk Port Security over EtherChannel</b>
Trunk port security over EtherChannel® is an extension of trunk port security where redundant links from a single station are connected to a Catalyst 4500/4900 using EtherChannel. The feature enables customers to block access to the Catalyst 4500/4900 by MAC addresses other than the ones specified (or learned) on EtherChannel trunk interfaces. It preserves all the advantages of port security and EtherChannel, including redundancy and load sharing. This feature is typically deployed in data center environments with dual NIC servers connecting to a Catalyst 4500/4900 using EtherChannel.
<b>Match CoS for Non-IPv4 Traffic</b>
The match class of service (CoS) feature helps a service provider to classify packets based on CoS values while preserving its customers' packet differentiated services code point (DSCP) values inside the service provider network. The match Cos for non-IPv4 feature provides uniform class-level quality-of-service (QoS) semantics irrespective of traffic type on a dot1q-tunnel and regular trunk ports. This is typically deployed in a Q-in-Q environment, where double-tagged IPv4 packets are forwarded as non-IPV4 packets.
<b>L2PT over Trunk</b>
Layer 2 Protocol Tunneling (L2PT) allows customer switches to participate in L2 protocols across a Service Provider network. This is achieved by encapsulating Layer 2 protocol packets, such as Cisco Discovery Protocol (CDP), Spanning -Tree Protocol (STP), or VLAN Trunking Protocol (VTP), before sending them across the service provider network. As a result the CPE switches on either side of the SP network can continue to process the L2 protocol control packets as if they were being received from a directly connected neighboring switch. The existing implementation allowed L2PT to be used only on tunnel ports. This feature will extend the functionality so that L2PT will be available on trunk ports configured with dot1q encapsulation.
<b>CoS Mutation</b>
The CoS mutation feature enables Service Providers to provide differentiated services for video, voice, and data within the SP network. In a typical L2 VPN offered by service providers, double tagged Q-in-Q traffic is forwarded with the outer tag representing service provider's VLAN and inner tag representing the customer's VLAN. SPs could either retain the CoS values from the customer tag in the service provider tag or change the CoS value of the outer service provider tag based on inner customer QoS matching and classification. As a result, Differentiated levels of service can be provided within the service provider network.
<b>IP Unnumbered for SVI</b>
IP unnumbered interface configuration enables IP processing on an interface without assigning it an explicit IP address. IP Unnumbered for SVI extends the current support for point-to-point links to switched virtual interfaces (SVIs). This feature is crucial in large service provider environments where SVIs are used to terminate L2 traffic from the CPE. This feature helps to conserve IP addresses space and, simplify configuration and address management.
