Cisco Intelligent Wireless Access Gateway User Manual

CHAPTER 3
Multiple-Flow Tunnel
A tunnel facilitates bidirectional transport or acts as a conduit for forwarding subscriber traffic. In PMIPv6,
subscriber traffic is transported between the MAG and the Local Mobility Anchor (LMA) through the Generic
Routing Encapsulation (GRE) tunnel. In the GTP, subscriber traffic is transported between the iWAG and
the GGSN through the GTP tunnel. The tunnel information structure is associated with each tunnel and
specifies common tunnel attributes, such as source address, destination address, protocol, port, key, tunnel
transport VRF, and tunnel mode.
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Finding Feature Information, page 33
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Information About Multiple-Flow Tunnel, page 33
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Additional References, page 34
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Feature Information for Multiple-Flow Tunnel, page 35
Finding Feature Information
Your software release may not support all the features documented in this module. For the latest caveats and
feature information, see Bug Search Tool and the release notes for your platform and software release. To
find information about the features documented in this module, and to see a list of the releases in which each
feature is supported, see the feature information table at the end of this module.
Use Cisco Feature Navigator to find information about platform support and Cisco software image support.
To access Cisco Feature Navigator, go to www.cisco.com/go/cfn. An account on Cisco.com is not required.
Information About Multiple-Flow Tunnel
Both the GTP and PMIPv6 support multiple flows per tunnel. A multiple-flow tunnel mechanism configures
and manages multiple flows of traffic within the same tunnel. Each flow is identified by a flow key. A flow
identifier or flow key is a 32-bit integer. The key is globally unique per system for the GTP. However, the
key can be unique per tunnel for PMIPv6. The flow key for the GTP is the Tunnel Endpoint Identifier (TEID),
and for PMIPv6, it is the GRE key. Each flow has parameters to describe the per-flow attributes.
PMIPv6 uses a multipoint GRE tunnel per LMA, and creates one adjacency per flow. An LMA can support
scaling numbers up to 128,000 MAG. From the LMA perspective, only one multipoint GRE tunnel interface
is created and 128,000 tunnel endpoints are populated. This scaling level supports the MAG functionality that
Intelligent Wireless Access Gateway Configuration Guide
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Cisco Intelligent Wireless Access Gateway Specifications

General

Brand	Cisco
Model	Intelligent Wireless Access Gateway
Category	Gateway
Language	English