Loopback IP Address

Loopback IP Address: 
The name itself talks about it. Want to know more on where how and why it is used.. Follow up with below paragraphs.
This ranges in 127.0.0.0 to 127.255.255.255. This address is not assigned to any of the real interfaces on the devices. Sometimes loop-back address is also used for management datagrams such as alarms originating from the equipment. 
At the end of this section i have mentioned one instance where i have used it practically. A loopback test and can be performed within a modem or transceiver by connecting its output to its own input. If this device receives its own signal back, this proves that the circuit is functioning. 

IP datagrams sent by a host to a 127.x.x.x loopback address are not passed down to the data link layer for transmission. Instead, they “loop back” to the source device at the IP level. 
Mostly this is used by developers for prototype testing in Initial phase. Using an IPV4 address and reserving it for usage as loopback address (when more such address required) would prove costly, as IP address availability is limited. Hence the IPV6(0:0:0:0:0:0:0:1) usage should help, but not sure about this. 

Practical Usage:
There was a customer who has reported an Alarm issue on a 2G-SGSN. This being a 2G-SGSN doesn't need any IU Interface to be configured, only Gb Interface IP configuration is needed.          
However, because of SGSN behavior the Alarm was raised for IU interface alarm missing. This is where loopback IP helped. The Alarm never popped up again after configuring this dummy loopback IP Address on IU interface. Hope this should be helpful as a workaround for the issues where Loopback can act as a substitute.

Thanks all.
 

Roadmap laid for 3GPP Release-12: Focus on Backhaul

I am excited to know that 3GPP has started to roll out the plans for freezing the content for Release-12 by end of 2014, even before the Telecom giants completed their implementation of Release 9 and 10.

Takehiro Nakamura, RAN Chairman has conducted a two day workshop which saw many participants who were the members of major telecom service providers from across the Globe, which focused on prioritizing the below areas.

1. Energy saving

2. Cost efficiency

3. Support for diverse application and traffic types

4. Backhaul enhancements

The first 3 terms are self explanatory and my interest here is to help you understand the Backhaul Enhancements.

Backhaul is the use of wireless communications systems to get data to/from an end user from/to a node. This also refer to the transmission of network data over an alternative route when the normal route is unavailable or congested. Example: The most common method of wireless backhaul involves microwave systems although satellites can also be used.

Here i think the challenge would be in choosing an appropriate backhaul solution that would fit the techno-economically. Lets wait to hear those details sooner.

MS Initiated PDP context deactivation with Bearer Control mode

Hi All,

My first technical writing on my favorite domain. Just want to share one of my work experiences.
I have come across a scenario where a subscriber has two PDP context activated.
One primary and one secondary. When during deactivation of PDP context, if Tear down Indicator is set for a PDP then all  the context relating to that particular PDP address has to be deactivated..
But in one particular case it is not same. When MS initiates Deactivation of Secondary PDP context with TDI set and its Bearer Control mode is 'MS/NW', then in that case the context that doesn't have a TFT would not be deactivated (Mostly this would be primary context).

The Bearer Control Mode (BCM) can be set to MS_only, MS/NW and NW_only based on the Protocol configuration Options field. More details of this can be found in 24.008 and 23.060.