Nat Binding Updates - Cisco ASR 5000 series Product Overview

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Table of Contents

▀ NAT Feature Overview

bearer ggsn-address: The PGW/GGSN address.

identifier are not applicable for PGW and GGSN.

NAT Binding Updates

Whenever a NAT IP address or NAT port-chunk is allocated/deallocated to/from a subscriber, to update NAT binding

information for that subscriber in the AAA, a NAT Binding Update (NBU) can be sent to the AAA server.

Since port-chunk allocation/deallocation happens on a per-call basis, this ensures that AAA messaging is reduced to a

great extent. NBUs are sent to the AAA server in accounting-interim messages. To send or not to send NBUs to the

AAA server is configurable in the NAT IP pool configuration.

NBUs are supported for both one-to-one and many-to-one NAT IP pools.

An NBU contains the following attributes:

Binding-Timer

Correlation-Id

Loading-Factor

NAT-IP-Address

NAT-Port-Block-End: In the case of one-to-one NAT, the value is 65535

NAT-Port-Block-Start: In the case of one-to-one NAT, the value is 1

CoA NAT Query

If the NAT binding information is not available at the AAA, the AAA server can query the chassis for the information.

This query uses the Change of Authorization (CoA) format, wherein the AAA sends a one-to-one NAT IP address as a

query, and in the CoA query response the NBU is obtained if available at the time of query.

The CoA query request must contain the following attributes:

Event-Timestamp

NAS-IP-Address

▄ Cisco ASR 5000 Series Product Overview

The NBR attributes: sn-correlation-id, sn-fa-correlation-id, radius-fa-nas-ip-address, radius-fa-nas-

In the case of P-GW, NBUs is not applicable since it does not use RADIUS.

In this release, CoA query for NAT binding information is only supported for one-to-one NAT.

Network Address Translation Overview