In Service Software Upgrade - Cisco Catalyst 4500 series Administration Manual

Chapter 1 Product Overview
OSPF uses the concept of an area, which is a group of contiguous OSPF networks and hosts. OSPF areas
are logical subdivisions of OSPF autonomous systems in which the internal topology is hidden from
routers outside the area. Areas allow an additional level of hierarchy different from that provided by IP
network classes, and they can be used to aggregate routing information and mask the details of a
network. These features make OSPF particularly scalable for large networks.
For details on OSPF, refer to this URL:
http://www.cisco.com/en/US/tech/tk365/tk480/tsd_technology_support_sub-protocol_home.html
RIP
The Routing Information Protocol (RIP) is a distance-vector, intradomain routing protocol. RIP works
well in small, homogeneous networks. In large, complex internetworks it has many limitations, such as
a maximum hop count of 15, lack of support for variable-length subnet masks (VLSMs), inefficient use
of bandwidth, and slow convergence. RIP II does support VLSMs.
For details on RIP, refer to this URL:
http://www.cisco.com/en/US/tech/tk365/tk554/tsd_technology_support_sub-protocol_home.html

In Service Software Upgrade

SSO requires the same version of Cisco IOS on both the active and standby supervisor engines. Because
of version mismatch during an upgrade or downgrade of the Cisco IOS software, a Catalyst 4500 series
switch is forced into operating in RPR mode. In this mode, after the switchover you can observe
link-flaps and a disruption in service. This issue is solved by the In-Service Software Upgrade (ISSU)
feature that enables you to operate in SSO/NSF mode while performing software upgrade or downgrade.
ISSU allows an upgrade or downgrade of the Catalyst IOS or IOS XE images at different release levels
on the both the active and standby supervisor engines by utilizing the Version Transformation
Framework between the stateful components running on each supervisor engine.
For details on Cisco IOS ISSU, refer to
Upgrade Process."
For details on Cisco IOS XE ISSU, refer to
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 the Catalyst 4500 series switch, see
"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:
OL-30933-01
Chapter 6, "Configuring the Cisco IOS In-Service Software
Chapter 7, "Configuring the Cisco IOS XE In Service
Software Configuration Guide—Release IOS XE 3.6.0E and IOS 15.2(2)E
Layer 3 Software Features
Chapter 55,
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