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Cisco Catalyst Blade Switch 3020 for HP Software Configuration Guide
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Chapter 35 Configuring IPv6 Host Functions
Understanding IPv6
HTTP(S) Over IPv6
The HTTP client in Cisco IOS supports sending requests to both IPv4 and IPv6 HTTP servers. The HTTP
server in Cisco IOS can service HTTP requests from both IPv4 and IPv6 HTTP clients. URLs with literal
IPv6 addresses must be formatted by using the rules listed in RFC 2732.
The accept socket call chooses an IPv4 or IPv6 address family according to protocol. The accept socket is
either an IPv4 or IPv6 socket. The listening socket continues to listen for both IPv4 and IPv6 signals indicat-
ing a connection. The IPv6 listening socket is bound to an IPv6 wildcard address.
The underlying TCP/IP stack supports a dual-stack environment. HTTP relies on the TCP/IP stack and the
sockets for processing network-layer interactions.
Basic network connectivity (ping) must exist between the client and the server hosts before HTTP connec-
tions can be made.
The output of these show commands can contain both IPv4 and IPv6 address types:
• show ip http server history
• show ip http server connection
• show ip http client connection
• show ip http client history
Dual IPv4 and IPv6 SDM Templates
The switch has one TCAM to store unicast routes, MAC addresses, ACLs, and other features. To allocate
TCAM resources for different usages, the switch SDM templates prioritize system resources to optimize
support for certain features. You select the template that best suits the switch environment by entering
the sdm prefer global configuration command. For more information about SDM templates, see
Chapter 6, “Configuring SDM Templates.”
The dual IPv4 and IPv6 templates allow the switch to be used in dual stack environments (supporting
both IPv4 and IPv6). If you try to configure IPv6 without first selecting a dual IPv4 and IPv6 template,
a warning message is generated.
Note If you do not plan to use IPv6, do not use the dual stack template because this template results in less
TCAM capacity for each resource. An IPv4 route requires only one TCAM entry. Because of the
hardware compression scheme used for IPv6, an IPv6 route can take more than one TCAM entry,
reducing the number of entries forwarded in hardware.
The switch does not support IPv6 routing, multicast routing, QoS, or most IPv6 ACLs. The switch does
support IPv6 Multicast Listener Discovery (MLD) snooping and input router IPv6 ACLs for control
traffic.
Table 35-1 defines the approximate feature resources allocated by each dual template. Template
estimations are based on a switch with eight routed interfaces and approximately one thousand VLANs.
Table 35-1 Approximate Feature Resources Allowed by Dual IPv4-IPv6 Templates
Resource
IPv4-and-IPv6
Default
IPv4-and-IPv6
Routing
IPv4-and-IPv6
VLAN
Unicast MAC addresses 2 K 1.5 K 8 K
IPv4 IGMP groups and multicast routes 1 K 1K 1 K
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