Gb Link Utilization

[mashi123]

any one has an idea has to calculate Gb link utilization in case of Gb over Frame relay

Thanks in advance

[electron]

hi friend,

You need to find how many E1 (or maybe 64K) link assigned from BSC to SGSN then calculate IP Volume in BSC peak hour then based on erlang table you can find utilization

[s52d]

Hi!

Erlang tables might not be the best one for packet systems.

I suggest you check peak bit rate and compare to E1 capacity (just 30 TS are used for FR, if I recall).
EIther SGSN or BSC counters can do. Both are best (and they might differer a bit)
It can be done also by summing up all BSC cells EDGE+GPRS traffic and applying some magic factor like 1.32
for BSS overhead.

A bit of congestion is no harm: it is packet system. But try to keep it low: once you start to
cut/drop signalling, you have problems.

As a side story: when you change to Gb/IP, be ready for noticeable increase on Gb traffic. IP overhead.

BR
s52d

[mashi123]

hi
I have huawei BSCs so i got the maximum throughput from the counters related to NSVC bytes sent and received
but should we take the sum of received(downlink) and sent(uplink) bytes or should we take received only
a lot of engineers told me that I should take downlink only but i m not convinced because AFAIK frame relay is packet based??????
can u clarify on this point

[s52d]

HI!

It depends what you need. E1 (or UTP) is simmetrical: so if you have 6 Mbit/s capacity,
it means 6 up, 6 down.
Usually, downlink exceeds uplink noticeable: thus, we consider only downlink.

In an rare retro case that both UL and DL share same capacity (RG58 10 Mbit/sec ethernet...) then you have to sum it up.

Also, in some weird licensing scenarios DL and UL are summed up.
So, you have to pay attention on what you are looking at.

BR
s52d

[mashi123]

I really appreciate your reply

[srilasitha]

Gb link utilization can be calculated with either with Peak DL data rate or Average DL data rate. Recommended way is to calculate with average DL data rate and if the utilization is above 80% then need to expand

[electron]

Guys still it is not clear ,

Please support for below doubt of mine:

suppose we have X E1 from BSC to SGSN and Peak IP Volume in DL for BSC is Y then how exactly we can calculate?
How much will be GOS value to calculate offered traffic(IP Volume) with X number of E1?

[s52d]

Guys still it is not clear ,

Please support for below doubt of mine:

suppose we have X E1 from BSC to SGSN and Peak IP Volume in DL for BSC is Y then how exactly we can calculate?
How much will be GOS value to calculate offered traffic(IP Volume) with X number of E1?

Hi!
GOS in PS domain is not as simple as voice.
In voice: if there is no TS, there is no call.
Packet: if Gb is congested, there are increased delays and some TCP level retries.
so:
Accesibility: (what we look into Erlnag tables for voice) is good untill you start rejecting PDPs.
Integrity (voice: PesQ, SQI etc) is where kbit/s comes.

On Gb: you really need heavy congestion in order to start rejecting PDPs.
But, some slow downs might be OK. Previous advice (keep peak hour average at 80% capacity) smells very decent.

I hardly recall E1 and FR on Gb, but we were already all red and pushy for more capacity, when first Gb related
complains popped up.

Last voice analogy: if Gb is occasionally congested, you get slow down. Like you start to use HR when you run out of FR TS in voice.


BR
s52d

[orazak]

hi
I have huawei BSCs so i got the maximum throughput from the counters related to NSVC bytes sent and received
but should we take the sum of received(downlink) and sent(uplink) bytes or should we take received only
a lot of engineers told me that I should take downlink only but i m not convinced because AFAIK frame relay is packet based??????
can u clarify on this point

In Huawei there is counter to show Gb utilisation, RL9610:Downlink bandwidth usage of the BC. We can use DL only because, it's much higher than UL