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Beginner

STS-1 ?

I'm hoping to get some clarification--and either the answer is obvious or I'm missing something. Currently we have a handful of 15327s in a ring, running USPR with about 40 T-1 circuits handling strictly voice traffic. It's entirely OC-12 with the exception of 1 span, which is OC-3.  When we set up optical circuits (8+ years ago) we chose STS-1. My questions are:

1. As we add more T-1s and the STS-1 fills, does it automatically build STS-2 for usage? I notice that on some of my nodes, under the Cross-Connect Resource Usage VT Matrix Port Detail, STS-1 is at 100% (or nearing it), and below it there is an STS-2.

2. Can I aslo surmise that since the Drop is the Source, that the STS number will increment based on my bandwidth? i.e. if the circuit source is on an OC-12 link, I can expect 12 total STSes?

3. I also notice that under the Summary I'm showing 5 of 196 in use for the STS-1 Matrix. Can someone tell me where the magic number of 196 comes from?

4. Just for clarification, again in the Summary area, the VT1.5 Matrix displays that only 95 of 672 are in use. I understand that 672 represents the total number of T-1s I can have. But is that a total number running thru that node? Or the total number I can have terminated on that node?  And since we only have about 40 circuits build (with a handfull being OOS), I assume that the 95 means that's the total number of circuits built and being passed thru that node. Is this correct?

Any answers would be GREATLY appreciated; it's been a long time since I took the class and these are questions I can't seem to answer by reading the class student guide, the procedure guides, or the reference manual.

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Accepted Solutions
Cisco Employee

Re: STS-1 ?

1. As we add more T-1s and the STS-1 fills, does it automatically build STS-2 for usage? I notice that on some of my nodes, under the Cross-Connect Resource Usage VT Matrix Port Detail, STS-1 is at 100% (or nearing it), and below it there is an STS-2.

No, it won’t build STS-2. Next available STS-1 will be used.

2. Can I aslo surmise that since the Drop is the Source, that the STS number will increment based on my bandwidth? i.e. if the circuit source is on an OC-12 link, I can expect 12 total STSes?

Yes. On OC12 link you can have in total up to 12 STSes. Creating new circuits new STS will be occupied.

3. I also notice that under the Summary I'm showing 5 of 196 in use for the STS-1 Matrix. Can someone tell me where the magic number of 196 comes from?

That is coming from cross-connect ASIC used on this card and that is a max number of STS this ASIC can provide for us.

4. Just for clarification, again in the Summary area, the VT1.5 Matrix displays that only 95 of 672 are in use. I understand that 672 represents the total number of T-1s I can have. But is that a total number running thru that node? Or the total number I can have terminated on that node?  And since we only have about 40 circuits build (with a handfull being OOS), I assume that the 95 means that's the total number of circuits built and being passed thru that node. Is this correct?

Yes. That is total: terminated and pass-through.
VT1.5 multiplexing is STS-based. The key VT matrix principles are as follows:
- The VT matrix has 24 logical STS ports. All VT1.5 multiplexing is achieved through these logical STS ports.
- Each VT matrix STS port has capacity for 28 VT1.5s. Therefore, the VT matrix has a capacity for 672 VT1.5 terminations.
- Because each logical STS termination on the VT matrix can carry 28 VT1.5s, the VT matrix capacity is 672 VT 1.5s (24 times 28).
The XTC card can map up to 24 STSs for VT1.5 traffic. Because one STS can carry 28 VT1.5s, the XTC card can terminate up to 672 VT1.5s or 336 VT1.5 cross-connects. However, to terminate 336 VT1.5 cross-connects:
- Each STS mapped for VT1.5 traffic must carry 28 VT1.5 circuits. If you assign each VT1.5 circuit to a different STS, the XTC card VT1.5 cross-connect capacity is reached after you create 12 VT1.5 circuits.
- ONS 15327s must be in a BLSR. Source and drop nodes in path protection (UPSR) or 1+1 (linear) protection have capacity for only 224 VT1.5 cross-connects because an additional STS is used for the protect path.

To maximize XTC VT1.5 cross-connect resources, you can tunnel VT1.5 circuits through ONS 15327 nodes. VT1.5 tunnels do not use VT matrix capacity at ONS 15327 pass-through nodes, thereby freeing the XTC card cross-connect resources for other VT1.5 circuits.

Regards,

/A

View solution in original post

3 REPLIES 3
Beginner

Re: STS-1 ?

* We chose STS-1 for each optical circuit* .....incase that sounded truncated.

Cisco Employee

Re: STS-1 ?

1. As we add more T-1s and the STS-1 fills, does it automatically build STS-2 for usage? I notice that on some of my nodes, under the Cross-Connect Resource Usage VT Matrix Port Detail, STS-1 is at 100% (or nearing it), and below it there is an STS-2.

No, it won’t build STS-2. Next available STS-1 will be used.

2. Can I aslo surmise that since the Drop is the Source, that the STS number will increment based on my bandwidth? i.e. if the circuit source is on an OC-12 link, I can expect 12 total STSes?

Yes. On OC12 link you can have in total up to 12 STSes. Creating new circuits new STS will be occupied.

3. I also notice that under the Summary I'm showing 5 of 196 in use for the STS-1 Matrix. Can someone tell me where the magic number of 196 comes from?

That is coming from cross-connect ASIC used on this card and that is a max number of STS this ASIC can provide for us.

4. Just for clarification, again in the Summary area, the VT1.5 Matrix displays that only 95 of 672 are in use. I understand that 672 represents the total number of T-1s I can have. But is that a total number running thru that node? Or the total number I can have terminated on that node?  And since we only have about 40 circuits build (with a handfull being OOS), I assume that the 95 means that's the total number of circuits built and being passed thru that node. Is this correct?

Yes. That is total: terminated and pass-through.
VT1.5 multiplexing is STS-based. The key VT matrix principles are as follows:
- The VT matrix has 24 logical STS ports. All VT1.5 multiplexing is achieved through these logical STS ports.
- Each VT matrix STS port has capacity for 28 VT1.5s. Therefore, the VT matrix has a capacity for 672 VT1.5 terminations.
- Because each logical STS termination on the VT matrix can carry 28 VT1.5s, the VT matrix capacity is 672 VT 1.5s (24 times 28).
The XTC card can map up to 24 STSs for VT1.5 traffic. Because one STS can carry 28 VT1.5s, the XTC card can terminate up to 672 VT1.5s or 336 VT1.5 cross-connects. However, to terminate 336 VT1.5 cross-connects:
- Each STS mapped for VT1.5 traffic must carry 28 VT1.5 circuits. If you assign each VT1.5 circuit to a different STS, the XTC card VT1.5 cross-connect capacity is reached after you create 12 VT1.5 circuits.
- ONS 15327s must be in a BLSR. Source and drop nodes in path protection (UPSR) or 1+1 (linear) protection have capacity for only 224 VT1.5 cross-connects because an additional STS is used for the protect path.

To maximize XTC VT1.5 cross-connect resources, you can tunnel VT1.5 circuits through ONS 15327 nodes. VT1.5 tunnels do not use VT matrix capacity at ONS 15327 pass-through nodes, thereby freeing the XTC card cross-connect resources for other VT1.5 circuits.

Regards,

/A

View solution in original post

Contributor

Re: STS-1 ?

1. As we add more T-1s and the STS-1 fills, does it automatically  build STS-2 for usage? I notice that on some of my nodes, under the  Cross-Connect Resource Usage VT Matrix Port Detail, STS-1 is at 100% (or  nearing it), and below it there is an STS-2.

1 STS-1 have 28T1 and you said you have used 40T1 so you are usinf more than one STS 1. It is upto you how you have using 20 on one 20 on other or 28 on one and 12 on other.

2.  Can I aslo surmise that since the Drop is the Source, that the STS  number will increment based on my bandwidth? i.e. if the circuit source  is on an OC-12 link, I can expect 12 total STSes?

If all are 15327 and in most of them you have populated OC 12 cards where as in one you have OC3 card. So OC 12 have 12 STS for receive and 12 for Transmit Total 24 STS1. . Whereas in OC3 you have total 6 STS 1

3.  I also notice that under the Summary I'm showing 5 of 196 in use for  the STS-1 Matrix. Can someone tell me where the magic number of 196  comes from?

Is it 196 or 192? If 192 then 15327 can terminate 2 OC48 UPSR ring. So it need a Crossconnect of Oc48 X 4=192 STS1. You circuit are configured in 5 of those STS1.

4.  Just for clarification, again in the Summary area, the VT1.5 Matrix  displays that only 95 of 672 are in use. I understand that 672  represents the total number of T-1s I can have. But is that a total  number running thru that node? Or the total number I can have terminated  on that node?  And since we only have about 40 circuits build (with a  handfull being OOS), I assume that the 95 means that's the total number  of circuits built and being passed thru that node. Is this correct?

1 STS 1=28 T1.

You have OC 12 link 28x12 = 336 for transmit and 336 for Receive. This is total number running through that node and you cannot terminate all T1. There are few slots to terminate T1 and you multiply No of T1 per card x No 0f Card. Simple OC3 box can terminate 0nly some number of T1 per box. You have 84 T1 so that you can have multiple customers per ring.  Yes you are using 95 either pass through or terminated.

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