P2P Session Recovery - Cisco ASR 5000 series Product Overview

Hide thumbs Also See for ASR 5000 series:

Table of Contents

▀ How P2P Works

Some protocols like BitTorrent and Orb use HTTP traffic for initial setup. If P2P analysis is done after HTTP, it

is possible that these protocols may go undetected.

Protocols like Skype use well known ports (like 80 & 443). In these scenarios, the HTTP engine reports these as

invalid packets. For protocol detection, it is desirable to have P2P detection before Deep Packet Inspection

Stateless detection of protocols based on signature will be easier when the P2P analysis is done before DPI.

P2P Session Recovery

Intra-chassis session recovery is coupled with SessMgr recovery procedures.

Intra-chassis session recovery support is achieved by mirroring the SessMgr and AAAMgr processes. The SessMgrs are

paired one-to-one with the AAAMgrs. The SessMgr sends checkpointed session information to the AAAMgr. ACS

recovery is accomplished using this checkpointed information.

(PSCs/PSC2s), one standby and three active. Per active CPU with active SessMgrs, there is one standby SessMgr, and

on the standby CPU, the same number of standby SessMgrs as the active SessMgrs in the active CPU.

There are two modes of session recovery, one from task failure and another on failure of CPU or PSC/PSC2.

Recovery from Task Failure

When a SessMgr failure occurs, recovery is performed using the mirrored ―standby-mode‖ SessMgr task running on the

active packet processing card. The ―standby-mode‖ task is renamed, made active, and is then populated using

checkpointed session information from the AAAMgr task. A new ―standby-mode‖ SessMgr is created.

Recovery from CPU or PSC/PSC2 Failure

When a packet processing card hardware failure occurs, or when a planned packet processing card migration fails, the

standby packet processing card is made active and the ―standby-mode‖ SessMgr and AAAMgr tasks on the newly

activated packet processing card perform session recovery.

This section lists the limitations of P2P detection in this release.

▄ Cisco ASR 5000 Series Product Overview

In order for session recovery to work there should be at least four packet processing cards

Peer-to-Peer Overview