telecom • networking • design

Debugging software crashes 2

This article continues our discussion on Debugging software crashes. Here we focus on memory corruption crash symptoms. We will also look at the special considerations in debugging C++ code crashes. Finally we will look at techniques to simplify crash debugging. The article covers the following topics: Debugging Memory Corruption Global Memory Corruption Heap Memory Corruption Stack Memory…

S1AP View of Inter-MME S1 Handover

Here we look at the S1 handover that involves an MME change. The S1 handover is analyzed at the S1AP interface. S1AP messages involved in S1 handover are shown just before the message. The messages show a high level structure of the complex messages involved in the interaction. Additionally, you can click on any S1AP message to see the complete field level details like the one shown below.

LTE Network Design and Planning Videos

Learn about LTE network design and planning from this video series. Issues involved in RF planning and resource allocation are covered in detail. The video tutorial series is divided into the following videos: dimensioning user traffic in 4G networks overhead in LTE dimensioning customer experience in wireless network design measurements in LTE downlink parameter dimensioning in LTE uplink…

DHCP: Dynamic Host Configuration Protocol

Dynamic Host Configuration Protocol (DHCP) is used to dynamically provide IP addresses and configuration information to client nodes. DHCP provides greater flexibility by leasing out IP addresses to host nodes. DHCP supports mechanisms that can be used by hosts to renew their lease. This sequence diagram describes the DHCP interactions between a Laptop and the DHCP servers in the intranet. Four…

BGP peering and route updates

BGP peering and route update messaging is explored in detail in this flow. This message flow shows how two BGP routers: Peer by establishing a TCP connection and exchanging BGP OPEN messages. Exchange Keep Alive messages to ensure that the routers are reachable. Exchange routes using BGP UPDATE messages. Release the BGP connection on operator command. All messages in this sequence diagram may be…

Tracking Area Updates in an LTE Network

LTE Tracking Area Update signaling flow describes how mobiles keep the network updated about their location. A Tracking Area Update takes place if: UE detects it has entered a new Tracking Area that is not in the list of TAIs that the UE registered with the network; the periodic Tracking Area update timer has expired; UE was in UTRAN PMM_Connected state (e.g. URA_PCH) when it reselects to E…

We have already covered object oriented design tips in a previous article. Here we will look at more tips that will help you improve your object oriented design skills:

Class with just get-set methods points to missed delegation

Replace an array of structures with an array of objects

Delegate work to helper class

Multi-dimensional arrays point to incomplete class identification

Multiple nested…

LTE random access procedure is used by the UEs to initiate a data transfer. The UEs also obtain uplink timing information from the initial handshake.

This sequence diagram describes the tale of three UEs (UE-A, UE-B and UE-C) that are powered on at the same time:

UEs synchronize with the downlink channel by decoding the PSS and SSS signal. The UEs are synchronized to the downlink frames…

This sequence diagram looks at LTE Attach and EPS Bearer Setup from the S1AP vantage point. The following signaling is covered:

UE Attach, authentication and security signaling

Setup of two EPS Bearers (RAB id 5 and 6)

Release of UE context due to inactivity

Reestablishment of the UE context with a Service Request.

You can click on individual messages in the sequence diagram to see field level…