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.g707

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

31 comments to SDH multiplex structure

  • Vijay Kumar

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

  • Abraham

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

  • admin

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

  • I want to know full form of KLM?

  • Azhar

    the KLM values table are easy to understand …
    the KLM numbering is what i saw in the cisco router config

    thanks anyway

  • SALEM

    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

  • Abdulla Munnim

    KLM = Keystroke-Level Model

  • Devendra

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

  • Ganapathy

    Thanks for explaining about SDH and KLM

  • Kunal Pimpalkar

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

  • Abdul Fathah MK

    Valuable information Thanx for the same

  • Ashok

    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.

  • najam

    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

  • Allah Ditta

    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.

  • kailash

    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?

  • Nevermore Mazongo

    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

  • Nevermore Mazongo

    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.

  • Thomaswar Chakma

    Good lession.

  • Taposh PAUL

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

  • admin

    Sorry, i don’t know.

  • NIkiso

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

  • Rubel

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

  • Allah ditta

    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

  • kushal khanal

    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).

  • shinu

    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 …..

  • Abdullah

    Hi all

    use this equation:

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

  • Hamad

    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!

  • Anthuvan Joseph

    Any idea about how to calculate JKLM or CBKLM

  • zaghum

    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

  • Abdullah

    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

  • Abdullah

    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

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