Cisco Cisco ASR 5000
Serving GPRS Support Node (SGSN) Overview
Features and Functionality ▀
SGSN Administration Guide, StarOS Release 18 ▄
Dual PDP Addresses for Gn/Gp
In accordance with 3GPP Release 9.0 specifications, it is now possible to configure SGSN support for dual stack PDP
type addressing (IPv4v6) for PDP context association with one IPv4 address and one IPv6 address/prefix when
requested by the MS/UE.
type addressing (IPv4v6) for PDP context association with one IPv4 address and one IPv6 address/prefix when
requested by the MS/UE.
ECMP over ATM
Iu Redundancy is the ASR 5000's implementation of equal-cost multi-path routing (ECMP) over ATM.
Iu Redundancy is based on the standard ECMP multi-path principle of providing multiple next-hop-routes of equal cost
to a single destination for packet transmission. ECMP works with most routing protocols and can provide increased
bandwidth when traffic load-balancing is implemented over multiple paths.
to a single destination for packet transmission. ECMP works with most routing protocols and can provide increased
bandwidth when traffic load-balancing is implemented over multiple paths.
ECMP over ATM will create an ATM ECMP group when multiple routes with different destination ATM interfaces are
defined for the same destination IP address. When transmitting a packet with ECMP, the NPU performs a hash on the
packet header being transmitted and uses the result of the hash to index into a table of next hops. The NPU looks up the
ARP index in the ARP table (the ARP table contains the next-hop and egress interfaces) to determine the next-hop and
interface for sending packets.
defined for the same destination IP address. When transmitting a packet with ECMP, the NPU performs a hash on the
packet header being transmitted and uses the result of the hash to index into a table of next hops. The NPU looks up the
ARP index in the ARP table (the ARP table contains the next-hop and egress interfaces) to determine the next-hop and
interface for sending packets.
EDR Enhancements
A new event-logging handle has been introduced. In earlier releases the EDR module was used for event logging
purpose, from this release onwards CDR_MODULE_EVENT_RECORD is used instead of CDR_MODULE_EDR. In
Release 12.0, for generating event logs the SGSN re-used the existing ‘EDR” module which is primarily used for
charging records. But from Release 15.0 onwards, the session-event module will be used by SGSN for event logging.
The CLI options present under the EDR Module are also present under the Session Event Module.
purpose, from this release onwards CDR_MODULE_EVENT_RECORD is used instead of CDR_MODULE_EDR. In
Release 12.0, for generating event logs the SGSN re-used the existing ‘EDR” module which is primarily used for
charging records. But from Release 15.0 onwards, the session-event module will be used by SGSN for event logging.
The CLI options present under the EDR Module are also present under the Session Event Module.
EIR Selection for Roaming Subscribers
EIR selelction for roaming subscribers functionality makes it possible for the SGSN to select an EIR based on the
PLMN into which the subscriber has roamed and reduce signalling back to home PLMNs for roamers.
PLMN into which the subscriber has roamed and reduce signalling back to home PLMNs for roamers.
The Equipment Identity Register (EIR), used for authentication and authorization during an Attach, is the carrier's
IMEI(SV) database of the unique numbers allocated to each subscriber’s mobile station equipment (IMEI) and the
manufacturer’s software version (SV). An IMEI(SV) can be in one of three lists in the EIR:
IMEI(SV) database of the unique numbers allocated to each subscriber’s mobile station equipment (IMEI) and the
manufacturer’s software version (SV). An IMEI(SV) can be in one of three lists in the EIR:
white list - the subscriber equipment is permitted access
black list - the subscriber equipment is not permitted access
grey list - the subscriber equipment is being tracked for evaluation or other purposes
As part of this function, the operator can create and use an EIR profile to define the parameters to:
use a single EIR address for multiple EIRs,
achieve the Check-IMEI-Request, and
associate the EIR profile with a call control profile.