Cisco ASR 901 Series Aggregation Services Router Software Configuration Guide
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Cisco ASR 901 Mobile
Wireless Router is a cell-site access platform specifically designed to
aggregate and transport mixed-generation radio access network (RAN) traffic.
The router is used at the cell site edge as a part of a 2G, 3G, or 4G radio
access network (RAN). The Cisco ASR 901 is availabe in the following models:
Cisco ASR 901-TDM version
(A901-12C-FT-D, A901-4C-FT-D, A901-6CZ-FT-D, A901-6CZ-FT-A)
Cisco ASR 901-Ethernet
version (A901-12C-F-D, A901-4C-F-D, A901-6CZ-F-D, A901-6CZ-F-A)
Cisco ASR 901
helps enable a variety of RAN solutions by extending IP connectivity to devices
using Global System for Mobile Communications (GSM), General Packet Radio
Service (GPRS), Node Bs using HSPA or LTE, Base Transceiver Stations (BTSs)
using Enhanced Data Rates for GSM Evolution (EDGE), Code Division Multiple
Access (CDMA), CDMA-2000, EVDO, or WiMAX, and other cell-site equipment.
Cisco ASR 901
transparently and efficiently transports cell-site voice, data, and signaling
traffic over IP
using traditional T1/E1 circuits,
including leased line, microwave, and satellite. It also supports alternative
backhaul networks, including Carrier Ethernet and Ethernet in the First Mile
Cisco ASR 901
also supports standards-based Internet Engineering Task Force (IETF) Internet
protocols over the RAN transport network, including those standardized at the
Third-Generation Partnership Project (3GPP) for IP RAN transport.
Custom designed for the cell
site, the Cisco ASR 901 features a small form factor, extended operating
temperature, and cell-site DC input voltages.
The Cisco ASR 901 TDM
version provides 12 Gigabit Ethernet ports, 16 T1/E1 ports and one Management
port. Whereas, the Cisco ASR 901 Ethernet version does not contain the 16 T1/E1
ports. It has only 12 Gigabit Ethernet ports and one management port.
Cisco ASR 901
supports Ethernet Virtual Circuits (EVC) only. Metro-Ethernet Forum (MEF)
defines an Ethernet Virtual Connection as an association between two or more
user network interfaces identifying a point-to-point or
multipoint-to-multipoint path within the service provider network. An EVC is a
within the service provider network.
A RAN is typically composed of thousands of BTSs
or Node Bs, hundreds of base station controllers or radio network controllers
(BSCs or RNCs), and several mobile switching centers (MSCs). The BTS or Node Bs
and BSC or RNC are often separated by large geographic distances, with the BTSs
or Node Bs located in cell sites uniformly distributed throughout a region, and
the BSCs, RNCs, and MSCs located at suitably chosen Central Offices (CO) or
mobile telephone switching offices (MTSO).
The traffic generated by a BTS or Node B is
transported to the corresponding BSC or RNC across a network, referred to as
the backhaul network, which is often a hub-and-spoke topology with hundreds of
BTS or Node Bs connected to a BSC or RNC by point-to-point time division
multiplexing (TDM) trunks. These TDM trunks may be leased-line T1/E1s or their
logical equivalents, such as microwave links or satellite channels.
The Cisco ASR 901 has two different types of
interfaces by default: network node interfaces (NNIs) to connect to the service
provider network and user network interfaces (UNIs) to connect to customer
networks. Some features are supported only on one of these port types. You can
also configure enhanced network interfaces (ENIs). An ENI is typically a
user-network facing interface and has the same default configuration and
functionality as UNIs, but can be configured to support protocol control
packets for Cisco Discovery Protocol (CDP), Spanning-Tree Protocol (STP),
EtherChannel Link Aggregation Control Protocol (LACP).
This section contains the following topics:
Autosensing of port speed and autonegotiation of duplex mode on all ports for optimizing bandwidth.
Automatic-medium-dependent interface crossover (auto-MDIX) capability on 100 and 100/1000 Mbps interfaces and on 100/1000
BASE-T/TX small form-factor pluggable (SFP) module interfaces that enables the interface to automatically detect the required
cable connection type (straight-through or crossover) and to configure the connection appropriately.
EtherChannel for enhanced fault tolerance and for providing up to 8 Gbps (Gigabit EtherChannel) or 800 Mbps (Fast EtherChannel)
full duplex of bandwidth between switches, routers, and servers.
Link Aggregation Control Protocol (LACP) for automatic creation of EtherChannel links (supported only on NNIs or ENIs).
Forwarding of Layer 2 and Layer 3 packets at Gigabit line rate.
CLI—You can access the CLI either by connecting your management station directly to the router console port or by using Telnet
from a remote management station. For more information about the CLI, see Using the Command-Line Interface
Cisco Configuration Engine—The Cisco Configuration Engine is a network management device that works with embedded Cisco IOS
CNS Agents in the Cisco ASR 901
Series Aggregation Services Router software. You can automate initial configurations and configuration updates by generating
router-specific configuration changes, sending them to the router, executing the configuration change, and logging the results.
SNMP—SNMP management applications such as CiscoWorks2000 LAN Management Suite (LMS) and HP OpenView. You can manage from an
SNMP-compatible management station that is running platforms such as HP OpenView or SunNet Manager.
For the list of MIBs
Cisco ASR 901
supports, see the Release Notes for
Cisco ASR 901
Address Resolution Protocol (ARP) for identifying a router through its IP address and its corresponding MAC address.
Cisco Discovery Protocol (CDP) Versions 1 and 2 for network topology discovery and mapping between the router and other Cisco
devices on the network (supported on NNIs by default, can be enabled on ENIs, not supported on UNIs).
Network Time Protocol (NTP) for providing a consistent time stamp to all routers from an external source.
Cisco IOS File System (IFS) for providing a single interface to all file systems that the router uses.
In-band management access for up to five simultaneous Telnet connections for multiple CLI-based sessions over the network.
Effective with Cisco IOS Release 15.3(2)S1, in-band management access for up to 98 simultaneous Telnet connections for multiple
CLI-based sessions over the network.
In-band management access for up to five simultaneous, encrypted Secure Shell (SSH) connections for multiple CLI-based sessions
over the network.
In-band management access through SNMP Versions 1 and 2c get and set requests.
Out-of-band management access through the router console port to a directly attached terminal or to a remote terminal through
a serial connection or a modem.
User-defined command macros for creating custom router configurations for simplified deployment across multiple routers.
Support for metro Ethernet operation, administration, and maintenance (OAM) IEEE 802.1ag Connectivity Fault Management (CFM),
Ethernet Line Management Interface (E-LMI) on customer-edge and provider-edge devices, and IEEE 802.3ah Ethernet OAM discovery,
link monitoring, remote fault detection, and remote loopback, and IEEE 802.3ah Ethernet OAM discovery, link monitoring, remote
fault detection, and remote loopback (requires the metro IP access or metro access image).
Configuration replacement and rollback to replace the running configuration on a router with any saved Cisco IOS configuration
CPU utilization threshold logs.
Password-protected access (read-only and read-write access) to management interfaces for protection against unauthorized
Configuration file security so that only authenticated and authorized users have access to the configuration file, preventing
users from accessing the configuration file by using the password recovery process.
Multilevel security for a choice of security level, notification, and resulting actions.
Automatic control-plane protection to protect the CPU from accidental or malicious overload due to Layer 2 control traffic
on UNIs or ENIs.
TACACS+, a proprietary feature for managing network security through a TACACS server.
RADIUS for verifying the identity of, granting access to, and tracking the actions of remote users through authentication,
authorization, and accounting (AAA) services.
Extended IP access control lists for defining security policies in the inbound direction on physical ports.
Extended IP access control lists for defining security policies in the inbound and outbound direction on SVIs.
Quality of Service and Class of Service Features
Configurable control-plane queue assignment to assign control plane traffic for CPU-generated traffic to a specific egress
Cisco modular quality of service (QoS) command-line (MQC) implementation
Classification based on IP precedence, Differentiated Services Code Point (DSCP), and IEEE 802.1p class of service (CoS) packet
fields, or assigning a QoS label for output classification
One-rate policing based on average rate and burst rate for a policer
Two-color policing that allows different actions for packets that conform to or exceed the rate
Aggregate policing for policers shared by multiple traffic classes
Table maps for mapping CoS, and IP precedence values
Queuing and Scheduling
Class-based traffic shaping to specify a maximum permitted average rate for a traffic class
Port shaping to specify the maximum permitted average rate for a port
Class-based weighted queuing (CBWFQ) to control bandwidth to a traffic class
Low-latency priority queuing to allow preferential treatment to certain traffic
Per-port, per-VLAN QoS to control traffic carried on a user-specified VLAN for a given interface.
Layer 3 Features
IP routing protocols for load balancing and for constructing scalable, routed backbones:
BGP Version 4
IS-IS dynamic routing
BFD protocol Bidirectional Forwarding Detection (BFD) Protocol to detect forwarding-path failures for OSPF, IS-IS, and BGP
IP routing between VLANs (inter-VLAN routing) for full Layer 3 routing between two or more VLANs, allowing each VLAN to maintain
its own autonomous data-link domain
Static IP routing for manually building a routing table of network path information
Equal-cost routing for load balancing and redundancy
Internet Control Message Protocol (ICMP) and ICMP Router Discovery Protocol (IRDP) for using router advertisement and router
solicitation messages to discover the addresses of routers on directly attached subnets
Layer 3 VPN
These features are
available only when the router is running the Advance Metro IP services.
Multiple VPN routing/forwarding (multi-VRF) instances in customer edge devices (multi-VRF CE) to allow service providers
to support multiple virtual private networks (VPNs) and overlap IP addresses between VPNs.
MPLS VPN is supported.
Router LEDs that provide port- and router-level status
Syslog facility for logging system messages about authentication or authorization errors, resource issues, and time-out events
Enhanced object tracking for HSRP clients (requires metro IP access image)
IP Service Level Agreements (IP SLAs) support to measure network performance by using active traffic monitoring (requires
metro IP access or metro access image)
IP SLAs EOT to use the output from IP SLAs tracking operations triggered by an action such as latency, jitter, or packet
loss for a standby router failover takeover (requires metro IP access or metro access image)
EOT and IP SLAs EOT static route support to identify when a preconfigured static route or a DHCP route goes down (requires
metro IP access or metro access image)
Embedded event manager (EEM) for device and system management to monitor key system events and then act on them though a policy
(requires metro IP access or metro access image)