Specifications

70
Release Notes for Cisco 7000 Family for Cisco IOS Release 12.1 T
78-10811-05
New and Changed Information
General Packet Radio Service Release 1.4
Platforms: Cisco 7200 series routers
Note General Packet Radio Service (GPRS) Release 1.4 is a specially licensed feature that is
available only through a controlled image release in Cisco IOS Release 12.1(3)T. GPRS
Release 1.4 is the recommended upgrade for both GPRS Release 1.2 (available in
Cisco IOS Release 12.1(1)GA) and GPRS Release 1.3 (available in Cisco IOS Release
12.1(2)GB). For more information about acquiring GPRS Release 1.4, please contact your
Cisco sales representative. Customer documentation for GPRS Release 1.4 is available on
Cisco.com and the documentation CD-ROM.
General Packet Radio Service (GPRS) is defined and standardized by the European standards body
ETSI. GPRS is an IP packet-based data service for GSM networks. The GPRS network essentially
consists of two major elements, the serving GPRS support node (SGSN) and gateway GPRS support
node (GGSN).
The GGSN is a wireless gateway that allows mobile cellular phone users to access the public data
network (PDN) or specified private IP networks. User sessions are connected from a mobile station
through a device called a Base Station Subsystem (BSS) and then to a Serving GPRS Service Node
(SGSN).
The connection between the SGSN and the GGSN is enabled through a protocol called the GPRS
Tunneling Protocol (GTP). Finally, the connection between the GGSN and the PDN is enabled through
the Internet Protocol (IP).
In order to assign mobile user sessions an IP address, the GGSN uses the Dynamic Host Configuration
Protocol (DHCP). To authorize and authenticate the remote users, the GGSN can use a RADIUS server.
DHCP and RADIUS services can be specified for the global configuration, using GPRS DHCP and
RADIUS commands, or for each access point configured for the GGSN.
HSRP Support for ICMP Redirects
Platforms: Cisco 7100 series, Cisco 7200 series, and Cisco 7500 series routers
The HSRP Support for Internet Control Message Protocol (ICMP) Redirects feature enables Internet
Control Message Protocol (ICMP) redirection on interfaces configured with the Hot Standby Router
Protocol (HSRP).
When running HSRP, it is important to prevent hosts from discovering the interface (or real) MAC
addresses of routers in the HSRP group. If a host is redirected by ICMP to the real MAC address of a
router, and that router later fails, then packets from the host are lost. Previously, ICMP redirect
messages were automatically disabled on interfaces configured with HSRP.
This feature now enables ICMP redirects on interfaces configured with HSRP. This functionality filters
outgoing ICMP redirect messages through HSRP, where the next-hop IP address may be changed to an
HSRP virtual IP address.