Cisco 3825 - Manual (Page 17)

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Cisco 3825 Mobile Wireless Edge Router Software Configuration Guide
OL-15667-03
Chapter 1 Overview of the Cisco 3825 Mobile Wireless Edge Router
Cisco IOS Software Features
Software Features
Standard Cisco IOS software features supported in the Cisco 3825 router for the RAN-O
implementation include:
Simple Services
• DHCP
• PPP
• NAT
• OSPF
• RIP
Intelligent Services
• QoS
• VPN
• IP Multicast
• Mobile IP/FA
• content caching
• MPLS
• L2TPv3
Other Services
• ACFC and PFC Handling During PPP Negotiation
• HSRP
• NTP
• SNMP
Redundancy Support
In a RAN-O application, to ensure availability, the backhaul links to a Cisco 3825 router are redundantly
cabled to the Cisco 2-port T1/E1-RAN card. This card, designed specifically for the
Cisco MWR 1941-DC-A router and Cisco 3825 router includes relays that activate the T1/E1 ports.
These relays allow “Y” cabling for router redundancy where the T1/E1 link is not redundant and default
to open. The relays are controlled by HSRP/redundancy protocol between the two routers connected to
the same T1/E1.
Note If you choose to use the Cisco 3825 router in a non-redundant configuration, you must close the relays
on the card using the standalone subcommand. Also, redundancy parameters are processed when the
router is booted up. These parameters cannot be changed “on the fly.”
HSRP
Cisco’s HSRP is used to control which router is active and which is standby. HSRP uses a priority
scheme to determine which HSRP-configured router is to be the default active router. Priority is
determined first by the configured priority value, then by the IP address. In each case, a higher value is
of greater priority.