## SDH multiplex structure

Synchronous Digital Hierarchy (SDH) is a CCITT standard for a hierarchy of optical transmission rates. Synchronous Optical Network (SONET) is an ANSI (American National Standards Institute) standard for North America, that is largely equivalent to SDH.

Both are widely spread technologies for very high speed transmission of voice and data signals across the numerous world-wide fiber-optic networks.

SDH and SONET are point-to-point synchronous networks that use TDM multiplexing across a ring or mesh physical topology.

The main difference between both standards are the some header/pointer informations and the transmission rates.

The base transport module of SDH is the synchronous transport module with a transmission rate of 155,52mbps (STM-1), SONET uses OC-1 (~51mbs) as base module.

#### SDH/SONET transmission rates

PDH (USA) | PDH (Europe) | SDH | SONET | |||
---|---|---|---|---|---|---|

Bit Rate (Mbps) | Name | Name | Container | Transport | Container | Transport |

40000 | STM-256 | STS/OC-768 | ||||

10000 | STM-64 | STS/OC-192 | ||||

2500 | STM-16 | STS/OC-48 | ||||

622 | STM-4 | STS/OC-12 | ||||

155 | STM-1 | STS/OC-3 | ||||

140 | E4 | VC4 | ||||

51 | STS/OC-1 | |||||

45 | DS-3/T3 | STS-1 SPE | ||||

34 | E3 | VC3 | ||||

8 | E2 | |||||

6 | DS-2/T2 | VT6 (not really used) | ||||

2 | E1 | VC12 | ||||

1,5 | DS-1/T1 | VT1.5 | ||||

0,064 | DS-0/T0 | E0/D64S |

#### SDH multiplex structure

The SDH multiplex structure shown in the picture is defined in ITU-T G.707 and describes how low order signals are multiplexed into higher multiplex levels.

#### KLM values

Imagine you have a large number of E1 customer aggregated on a *PA-MC-STM-1SMI* (Cisco) or a *PE-1CHSTM1-SMIR-QPP* (Juniper).

The low order signal is transported over an SDH network, through the númerous multiplex levels, and is terminated on your channelized STM-1 card.

For configuring the customers interface on the aggregation device, you need to know in which timeslot the customers E1 resides.

–> This position is specified by the KLM values.

Here’s an overview for the KLM values of a STM-1:

Timeslot | TUG-3 | TUG-2 | VC-12 (–> E1) | KLM |
---|---|---|---|---|

1 | 1 | 1 | 1 | 1.1.1 |

2 | 1 | 1 | 2 | 1.1.2 |

3 | 1 | 1 | 3 | 1.1.3 |

4 | 1 | 2 | 1 | 1.2.1 |

5 | 1 | 2 | 2 | 1.2.2 |

6 | 1 | 2 | 3 | 1.2.3 |

7 | 1 | 3 | 1 | 1.3.1 |

8 | 1 | 3 | 2 | 1.3.2 |

9 | 1 | 3 | 3 | 1.3.3 |

10 | 1 | 4 | 1 | 1.4.1 |

11 | 1 | 4 | 2 | 1.4.2 |

12 | 1 | 4 | 3 | 1.4.3 |

13 | 1 | 5 | 1 | 1.5.1 |

14 | 1 | 5 | 2 | 1.5.2 |

15 | 1 | 5 | 3 | 1.5.3 |

16 | 1 | 6 | 1 | 1.6.1 |

17 | 1 | 6 | 2 | 1.6.2 |

18 | 1 | 6 | 3 | 1.6.3 |

19 | 1 | 7 | 1 | 1.7.1 |

20 | 1 | 7 | 2 | 1.7.2 |

21 | 1 | 7 | 3 | 1.7.3 |

22 | 2 | 1 | 1 | 2.1.1 |

23 | 2 | 1 | 2 | 2.1.2 |

24 | 2 | 1 | 3 | 2.1.3 |

25 | 2 | 2 | 1 | 2.2.1 |

26 | 2 | 2 | 2 | 2.2.2 |

27 | 2 | 2 | 3 | 2.2.3 |

28 | 2 | 3 | 1 | 2.3.1 |

29 | 2 | 3 | 2 | 2.3.2 |

30 | 2 | 3 | 3 | 2.3.3 |

31 | 2 | 4 | 1 | 2.4.1 |

32 | 2 | 4 | 2 | 2.4.2 |

33 | 2 | 4 | 3 | 2.4.3 |

34 | 2 | 5 | 1 | 2.5.1 |

35 | 2 | 5 | 2 | 2.5.2 |

36 | 2 | 5 | 3 | 2.5.3 |

37 | 2 | 6 | 1 | 2.6.1 |

38 | 2 | 6 | 2 | 2.6.2 |

39 | 2 | 6 | 3 | 2.6.3 |

40 | 2 | 7 | 1 | 2.7.1 |

41 | 2 | 7 | 2 | 2.7.2 |

42 | 2 | 7 | 3 | 2.7.3 |

43 | 3 | 1 | 1 | 3.1.1 |

44 | 3 | 1 | 2 | 3.1.2 |

45 | 3 | 1 | 3 | 3.1.3 |

46 | 3 | 2 | 1 | 3.2.1 |

47 | 3 | 2 | 2 | 3.2.2 |

48 | 3 | 2 | 3 | 3.2.3 |

49 | 3 | 3 | 1 | 3.3.1 |

50 | 3 | 3 | 2 | 3.3.2 |

51 | 3 | 3 | 3 | 3.3.3 |

52 | 3 | 4 | 1 | 3.4.1 |

53 | 3 | 4 | 2 | 3.4.2 |

54 | 3 | 4 | 3 | 3.4.3 |

55 | 3 | 5 | 1 | 3.5.1 |

56 | 3 | 5 | 2 | 3.5.2 |

57 | 3 | 5 | 3 | 3.5.3 |

58 | 3 | 6 | 1 | 3.6.1 |

59 | 3 | 6 | 2 | 3.6.2 |

60 | 3 | 6 | 3 | 3.6.3 |

61 | 3 | 7 | 1 | 3.7.1 |

62 | 3 | 7 | 2 | 3.7.2 |

63 | 3 | 7 | 3 | 3.7.3 |

This is good litrature but I want to know more detailes about SDH,KLM, Frame Structure and its Components

Really easy to understand, What is the abbreviated word for KLM ?

Sorry, i don’t know what it stands for.

I want to know full form of KLM?

the KLM values table are easy to understand …

the KLM numbering is what i saw in the cisco router config

thanks anyway

I am also looking for the abreviation of KLM.

I want also to know the KLM used by different vendors( NSN,Alcatel_luccent ,Huwaei…)

thankx

KLM = Keystroke-Level Model

How this KLM are designed.Plz give more details information regarding the KLM with the example to understand in big canvas

Thanks for explaining about SDH and KLM

This is really nice document.It clears all the queries about the KLM numbering.Thank you..

Valuable information Thanx for the same

Hi,

There is no abrvn for KLM.K varies from 1 to 3 L varies from 1 to 7 and M varies from 1 to 3.Total 63 E1s in one STM.

One E1 contains 2.048 Mbps data rate. Total 2.048*63=129Mbps and rest 26 for overhead.

Hi dear,

I think its in SDH there are 9 segments each segment contains 270 bytes of data in which 261 bytes are for payload & 9 bytes for OverHead so, 9*270bytes=2430bytes & sampling rate is 64k so we have 2430*64=155.52Mbps

Dear all I want to explain you KLM formula.There are two types to represent E’1. first is sequential and other one is interleaved.Let us discuss first one.

formula k+3(L-1)+21(M-1). for exampe you want to represent E#56 sequantially

3+3(5-1)+21(2-1)(====3+3*4+21*1======3+12+21=36 where K=3 represents tug 3,L represents tug2 and M represents Vc12.If you want to show it in KLM this would be 352

Now for interleaved number i-e which E1 number of STM1 this is we only change the formula.21(k-1)+3(L-1)+M by putting values.

21(3-1)+3(5-1)+2= =21*2+3*5+2=42+12+2=56 which shows if you are given 352 and asked to tell which E1# this is you can easily answer that it is 56th E1.

Hi Allah,

All the details for KLM is very brief and i like it, but i want to know if a E1 number is given and asks to find the corresponding KLM, then what? Is there any formula to obtain the KLM value?

If you are given an E1 number, N, and you want the corresponding KLM number.You proceed as follows:

Step 1. N/21 = Q Remainder R (Q=Quotient, R=Remainder) Q and R are both integers.

If R=0 then K = Q Else K = Q+1.

Alternatively: For 1 <= N <= 21 K = 1

For 22<= N <= 42 K = 2

For 43<= N <= 63 K = 3

Step 2. For 1<=N<=21 N/3 = Q Remainder R. If R = 0 then L = Q, Else L = Q + 1.

For 22<=N<=42 N-21=P, P/3 = Q Remainder R. If R = 0 then L = Q, Else L = Q + 1.

For 43<=N<=63 N-42=P, P/3 = Q Remainder R .If R = 0 then L = Q ,Else L = Q + 1.

Step 3. N/3 = Q Remainder R,

If R = 0 then M = 3, Else M = R.

Example:

Given E1 = 56

Step 1. 56/21 = 2 Remainder 14. Since R=14 is not equal to Zero, then K = 2+1 = 3.

Step 2. 42 < 56 < 63 then 56-42 = P = 14. Now 14/3 = 4 remainder 2.Since R = 2 and 2 is not equal to zero, then L = 4+1=5

Step 3. 56/3 = 18 Remainder 2.Since R=2 is not equal to zero, then M =R=2.

Therefore the KLM number for E1#56 is 3.5.2

Yes Kailash. This is how you do it.Given E1 number N and you want the K.L.M then proceed as follows;

Step1: N/21 = Q1 remainder R1. If R1 = 0, then K = Q1.Else K = Q1+1.

Step 2: R1/3 = Q2 remainder R2. If R2 = 0 then L = Q2.Else L = Q2+1.

Step 3: N/3 = Q3 remainder R3. If R3 = 0 then M = 3. Else M = R3.

Example: What is K.L.M for E1 57?

Step 1: 57/21 = 2 remainder 15. Therefore K = 2+1 = 3.

Step 2: 15/3 = 5 remainder 0. Therefore L = 5.

Step 3: 57/3 = 19 remainder 0. Therefore M = 3.

So the K.L.M for E1#57 is 3.5.3

Sometimes you want to convert from KLM to ITU-T mode. You proceed as follows:

Given K.L.M as N1.N2.N3 then

ITU-T mode is N3.N2.N1

Example: Converting KLM 2.4.3 to ITU-T Mode yields 3.4.2. Thats you map E1#33 to 53 to match two interfaces using the two different modes.

Now you are given KLM for an E1.How do you calculate the E1 number? Proceed as follows:

If K.L.M = K.7.3 then N = 21 * K. E.g 3.7.3 coresponds to 21*3 = E1#63.

If K.L.M = K.L.3 then N = 21(K-1) + 3*L. E.g 3.4.3 corresponds to 21(3-1) + 3*4 = 42 + 12 = 54. 3.3.3 corresponds to E1#54.

Generally Speaking N = 21(K-1) + 3(L-1) + M: for M not equal to 3 and L not equal to 7.

Good lession.

What is the KLM values for ALCATLE??????

Sorry, i don’t know.

It’s really good article. Thank you for explaining KLM.

This instruction is excellent, earlier i couldn’t find out this type of material regarding SDH & KLM

Attention Mr Taposh PAUL

Values of KLM are not desined acoording to any company’s product(ALCATEL or any else) but this is designed by ITU and remains same for all products,because this is the way of representing only consective E1’s.My friends if I could not be help full to questioner kindly write in details if any body could write. thnx

Yes, KLM doesn’t have full-form.Its just the notation for level of multiplexing.K(TUG-3) varies from 1 to 3(because 3 TUG-3 makes a VC-4, L(TUG-2) varies from 1 to 7(because 7 TUG-2 makes a TUG-3) and M(VC-12) varies from 1 to 3(becuase 3 VC-12 make a TUG-2).

Hi…Allah Ditta

Here u mention that E1 number =K+3(L-1)+21(M-1).

consider KLM 271

2+3*6+21*0=20

Actually the E1 number of 271 is 40.

Second method.

21(K-1)+3(L-1)+M

21*1+18+1=40its ok.

please clarify …..

Hi all

use this equation:

TU#[1-63]= K + (L-1)*9 + (M-1)*3

Dear Abdulla.

Your equation (TU#[1-63]= K + (L-1)*9 + (M-1)*3) seems wrong, see the example below:

Timeslot 36 = KLM 2.5.3

If we use your equation to find out which timeslot KLM 2.5.3 equals:

TU# = K + (L-1)*9 + (M-1)*3

= 2 + (5-1)*9 + (3-1)*3

= 2 + (4)*9 + (2)*3

= 2 + 36 + 6

= 44

For KLM 2.5.3, your equation gives us timeslot 44, but in reality, it should be timeslot 36!

Any idea about how to calculate JKLM or CBKLM

KLM it stands for nothing just we use this abbrivation for our convinience..

instead of speaking that

number of vc-12’s or E1’s = 10

number of tug 2’s = 12

number of tug 3’s = 15

for our convenience we just denote

number of vc-12’s or E1’s with K

number of tug 2’s with L

number of tug 3’s with M

and simply says k=10

L=12

M=15

if u still have any doubt then ask me again

Dear Hamad,

the equation is valid. the KLM for 2.5.3 is 36 and and the KLM for 44 is 3.4.3

Have a great day

Please note that the time slot numbering above is not correct.

it should be:

1

4

7

2

5

6

3

6

9

10

11

12

13

16

11

14

17

.

.

.

.

.

57

60

63