Cisco ASR 903 Release Notes page 25

Chapter
BGP Graceful Shutdown—The BGP Graceful Shutdown feature reduces or eliminates the loss of
•
traffic along a link being shut down for maintenance. Routers always have a valid route available
during the convergence process. This feature is used primarily for maintenance on a link between a
PE and CE. For more information, see
http://www.cisco.com/en/US/docs/ios-xml/ios/iproute_bgp/configuration/xe-3s/irg-grace-shut.htm
l.
Channelization Support—This release introduces support for channelization on the OC-3 interface
•
module using the channel-group command. For more information, see
http://www.cisco.com/en/US/docs/routers/asr903/software/guide/chassis/Release3.7.0S/ASR903-
Chassis-SW-37.html.
DHCP Option 82—In residential, metropolitan Ethernet-access environments, DHCP can centrally
•
manage the IP address assignments for a large number of subscribers. When the DHCP option-82
feature is enabled on a switch, a subscriber device is identified by the switch port through which it
connects to the network in addition to its MAC address. Multiple hosts on the subscriber LAN can
be connected to the same port on the access switch and are uniquely identified.For more information,
see http://www.cisco.com/en/US/docs/wireless/asr_900/feature/guides/dhcp82.html.
• DHCP Snooping—DHCP snooping is a DHCP security feature that provides network security by
filtering untrusted DHCP messages and by building and maintaining a DHCP snooping binding
database, also referred to as a DHCP snooping binding table. DHCP snooping acts like a firewall
between untrusted hosts and DHCP servers. You use DHCP snooping to differentiate between
untrusted interfaces connected to the end user and trusted interfaces connected to the DHCP server
or another switch. For more information, see
http://www.cisco.com/en/US/docs/wireless/asr_900/feature/guides/dhcp82.html.
• Dynamic ARP Inspection—Dynamic ARP inspection determines the validity of an ARP packet
based on valid IP-to-MAC address bindings stored in a trusted database, the DHCP snooping
binding database. This database is built by DHCP snooping if DHCP snooping is enabled on the
bridge-domains and on the router. If the ARP packet is received on a trusted interface, the router
forwards the packet without any checks. On untrusted interfaces, the switch forwards the packet
only if it is valid. For more information, see
http://www.cisco.com/en/US/docs/wireless/asr_900/feature/guides/dynarp.html.
• E2E Transparent Clocking—A transparent clock is a network device such as a switch that calculates
the time it requires to forward traffic and updates the PTP time correction field to account for the
delay, making the device transparent in terms of timing calculations. The transparent clock ports
have no state because the transparent clock does not need to synchronize to the grandmaster clock.
An end-to-end transparent clock measures the residence time of a PTP message and accumulates the
times in the correction field of the PTP message or an follow-up message. For more information, see
http://www.cisco.com/en/US/docs/routers/asr903/software/guide/chassis/Release3.7.0S/ASR903-
Chassis-SW-37.html.
GOLD—Generic Online Diagnostic (GOLD) is a health monitoring feature implemented on the
•
Cisco ASR 903 Router. The GOLD functionality is developed to provide online diagnostic
capabilities that run at bootup, in the background on a periodic basis, or based on demand from the
CLI. For more information, see
http://www.cisco.com/en/US/docs/wireless/asr_900/feature/guides/GOLD.html.
• Hot Standby Pseudowire Support—The Hot Standby Pseudowire feature provides faster failover of
a backup pseudowire and reduced traffic loss during failover by setting the backup pseudowire to a
hot standby state, such that it can immediately take over if the primary pseudowire fails. This feature
is supported for Ethernet only; TDM and ATM interfaces are not supported. For more information,
see:
–
OL-26630-08
http://www.cisco.com/en/US/docs/routers/7600/install_config/ES40_config_guide/es40_chap6.
html.
New Software Features in Cisco IOS XE Release 3.7(0)S
Cisco IOS XE 3S Release Notes for the Cisco ASR 903 Router
3