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Network Transport flow management for 3/4G networks

IP.com Disclosure Number: IPCOM000248799D
Publication Date: 2017-Jan-12
Document File: 3 page(s) / 91K

Publishing Venue

The IP.com Prior Art Database

Abstract

This article is describing techniques of how to manage transport layer flows (TCP/UDP) for tapping solution in core mobile operator networks taking in account limited hardware resources, specifics of mobile network connections setup and transport flow life time related issues.

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Network Transport flow management for 3/4G networks

Along the other technical difficulties, usually encountered in packet sniffing and network probing solutions over mobile networks is the management of TCP/UDP Flows of the actual data flows lifecycle. The state machines are created to manage the underlying transport protocols (TCP.UDP/SCTP) lifecycle. Those state machines need significant amount of memory and CPU resources, which forces to invent smarter to manage them. Problem definition

The probing server is required to manage data flows for all customers in a given probing site. The important problems, which probing solution needs to solve in order to produce network KPIs, are the management and processing of the transport flows. From processing perspective, the following issues are going to dominate:

- Initialisation of state machines flow specific information - Distribution of network packets which belongs to each flow - De-initialisation of state machines and returning the resource back to system - Management of flow abnormalities and network issues. - Other issues (packet losses, packer order and fragmentation and etc). Some transport protocols require more management efforts (like TCP, SCTP), others

less, UDP for example. This article will describe 2 methods, which can be used to manage and support in data

collection and probing solutions. TCP protocol us used as an active example, but the same can be extended for UDP protocol as well, or any other transport protocol which requires the maintenance. Session cache

Keeping all TCP connection for all active users is expensive from the memory prospective. This is where session cache helps to track all TCP session without losing of important information.

In the session cache system stores vital information about the session, like IP addresses and port, name of L7 application protocol (for example: Skype, Facebook, Twitter). Additionally, session cache can store information about flow state and sequence numbers to handle the issues, like lost packets, re-transmissions and etc. Information unit stored in session cache for individual TCP sessions called: “connection snapshot”. The 4 tuple <Source IP, Source Port, Destination IP, Destination Port> is naturally selected key or each connection snapshot.

Session cache can store more detailed information about TCP session and L7 application, however accurate consideration needs to be applied to store more items, since more information store, more performance penalty will be applied to connection restoration procedure. We will recommend to store only minimal required set for the current need of the pro...