CEPT NET 2 E-1988 Approval Requirements for Data Terminal Equipment to Connect to Packet Switched Public Data Networks Using CCITT Recommendation X 25 (1984) Interface (T TE 04-06E.pdf

1、CEPT NET*Z 88 2326414 0000068 O - NET 2 First edition: 1988 TRAC TECHNICAL RECOMMENDATIONS APPLICATION COMMITTEE EUROPEAN TELECOMMUNICATION STANDARD Approval requirements for data terminal equipment to connect to packet switched public data networks using CCITT Recommendation X.25 (1984) interface C

2、onditions dcigririent yoin. le raccordemetit dquipemetits termiiiniix de traitement de dorines ir im rseau public yoiir domtes ri commutntion par paquets titilismit liiiteiface cijinie dans Ia Recommnndatioii X.25 (1984) di CCITT N1 bits) 9.5.4 Extra long frame, - I) VS should be done after having w

3、aited a minimum of T1. DTE RR/F = 1 N(R) = b RR/F = 1 N(R) = b Expected behaviour from the DTE Note U Discard Discard 1) Discard Discard 11 CEPT NET*2 8 S 2326434 0000085 O I 9.6 Frame Abort should discard aborted frames. In this section the tester transmits I-frames. During this transmission the te

4、ster performs a frame abort. The DTE Test condition: The DTE shall be in the information transfer phase. Tester DTE IS: RR/P = 1 N(R) = a . i RR/F = 1 N(R) = b VS: RR/P = 1 N(R) = a RR/F = 1 N(R) = b Tests : Tester Expected behaviour acting as DCE N(R) out of sequence, aborted Discard from the DTE 9

5、.6.1 I-frame, . Note 1) 9.6.2 I - f r a m e, N(S) out of sequence, aborted Discard 1) VS should be done after having waited a minimum of T1. 9.7 or to ask the DCE to initiate a link Set-up. DTE reaction to unsolicited responses with F = X In this section, the tester transmits a response frame which

6、should cause the DTE to either initiate a link resetting, Test condition: The DTE shall be in the information transfer phase. Tester DTE IS: RR/P = 1 N(R) = a . RR/P = 1 N(R) = b Tests: Tester Expected behaviour acting as DCE from the DTE 9.7.1 UA/F = X - SABM/P = 1 9.7.2 RR/F = 1 . SABM/P = 1 9.1.3

7、 DM/F = 1 SABM/P = 1 1) Alternatively, the DTE may send DM/F = O. 9.8 Reject Procedure a REJ frame. In the third test the tester transmits a REJ; the DTE should retransmit the requested I-frames. In this section the reject procedure is tested. In the first and the second test the tester forces the D

8、TE to transmit Test condition: The DTE shall be in the information transfer phase. Tester DTE IS: RR/P = 1 N(R) = a . Tests: RR/F = 1 N(R) = b Tester Expected behaviour acting as DCE P = ON(S) = b + 3 from the DTE 9.8.1 I-frame, . REJ/F = O N(R) = b 3) I-frame 3) This test leaves the DTE in the REJ

9、condition and therefore the link must be reset prior to any subsequent test. Note CEPT NET*2 88 2326434 000008b 2 9.8.2 I-frame, L P= lN(S)=b+3 I-frame + u REJ/F = 1 N(R) = b 9.8.3 I-frame, L N(S) = bN(R) = a u RRN(R) = b + 1 I-frame N(S) = a N(R) = b + 1 I-frame, L N(S) = b + 1 N(R) = a u RRN(R) =

10、b + 2 . u I-frame N(S) = a + 1 N(R) = b + 2 I-frame N(S) = a N(R) = b + 2 I-frame N(S) = a + 1 N(R) = b + 2 REJ N(R) = a d 1) 2) 3) This frame may be omitted. The tester does not transmit an acknowledgment of the previous DTE frame. This test leaves the DTE in the REJ condition and therefore the lin

11、k must be reset prior to any subsequent test. 9.9 Flow Control second test the tester flow controls using a RNR frame. In this section the flow control mechanisms are tested. In the first test the window mechanism is used. In the Test condition: The DTE shall be in the information transfer phase. Te

12、ster DTE RR/P = 1 N(R) = a IS : a RR/F = 1 N(R) = b Tests : Tester acting as DCE Expected behaviour from the DTE Note 9.9. i This test should be done within the T1 of the DTE. T1 is started upon transmitting the first I-frame by the DTE. I-frame, N(S) = b N(R) = a I-frame, N(S) = b + 1 N(R) = a I-fr

13、ame, N(S) = b + 2 N(R) = a I-frame, N(S) = b + 3 N(R) = a I-frame, N(S) = b + 4 N(R) = a I-frame, N(S) = b + 5 N(R) = a I-frame, N(S) = b + 6 N(R) = a 1) RRN(R) = b + 1 I-frame N(S) = a N(R) = b + 1 1) RR N(R) = b + 2 I-frame N(S) = a + 1 N(R) = b + 2 1) RRN(R) = b + 3 I-frame N(S) = a + 2 N(R) = b

14、+ 3 1) RRN(R) = b + 4 I-frame N(S) = a + 3 N(R) = b + 4 . 11 RRN(R) = b + 5 I-frame N(S) = a + 4 N(R) = b + 5 1) . RR N(R) = b + 6 I-frame N(S) = a + 5 N(R) = b + 6 I) RR N(R) = b + 7 I-frame N(S) = a + 6 N(R) = b + 7 1) This frame may be omitted. . 13 NET 2 CEPT NET*Z 88 2326434 O000087 4 I-frame,

15、. N(S) = b + 7 N(R) = a RRN(R) = b + 8 The DTE should stop sending I-frames. I-frame, . RR/P = 1 L N(S) = b + 8 N(R) = a RRN(R) = b + 9 N(R) = a + 7 a RR/F = 1 N(R) = b + 9 I-frame N(S) = a + 7 N(R) = b + 9 I-frame N(S) = a + 8 N(R) = b + 9 9.9.2 RNR/P = 1 - I-frame, . I-frame, - N(R) = a RR/F = 1 N

16、(R) = b N(S) = bN(R) = a 2) a RRN(R) = b + 1 N(S) = b + 1 N(R) = a RRN(R) = b + 2 The DTE may send one I-frame but should not send the second one until the DCE ends or leaves the busy condition. RR/P = 1 . N(R) = a RR/F = 1 N(R) = b + 2 1 or 2 I-frames 1) 2) This frame may be omitted. This frame may

17、 be omitted if the DTE sends an I-frame. 9.10 Disconnected Ph-ase In this section, tests are described while the DTE and the DCE are in the Disconnected Phase. Test condition: The DTE and the DCE must be in the Disconnected Phase. Tester IS: DISC/P = 1 Tests: Tester acting as DCE DTE . UA/F = 1 or D

18、M/F = 1 Expected behaviour from the DTE 9.10.1 RR/P = 1 . DM/F = 1 9.10.2 DISC/P = 1 a DM/F = 1 9.10.3 I-frame/P = 1 - a DM/F = 1 9.1 1 Miscellaneous Tests Test condition: The DTE shall be in the information transfer phase. Tester IS : RR/P = 1 VS: RR/P = 1 Tests: Tester acting as DCE 9.11.1 RR/P =

19、1 DTE - L RR/F = 1 DM/F = I Expected behaviour from the DTE L RR/F = 1 14 NET 2 7 - Note CEPT NET*2 88 I 2326434 O000088 6 I 9.11.2 I-frame i RR I-frame/P = X DM/F = P . The DTE should enter the Disconnected Phase and may initiate link Set-up. 9.1 1.3 FRMR/F = X u L SABM/P = 1 1) VS should be done.

20、2) 3) This frame may be omitted. Alternatively, the DTE may send DM/F = O. 10 Packet Level Requirements (a) The tests in this section are designed to check that the DTE has implemented packet level in a manner acceptable for the granting of attachment approval. Compliance shail be checked by the fol

21、lowing tests as applicabe. (b) In this section tests 10.1, 10.2 and 10.3 apply to bothPVCs and SVCs. The remainder of the tests covering call setup and clearing apply only to SVCs. (c) Each packet level test consists of the following sequence of events: - an Initialisation Sequence (IS) to force the

22、 DTE into the desired test condition - performing the test sequence - observing the DTE behaviour - where the sequence terminates in a packet flowing from the tester to the DTE: a Verification Sequence (VS) to verify the DTE state It is possible that a test sequence will cause the DTE to invoke alte

23、rnative recovery and react in the following manner: - being in state rl at any time: - for LCs assigned as SVC being in any state except p6 and p7: - for LCs assigned as SVC, being in state p4, dl: discard the received packet and send a Restart Request, discard the received packet and send Clear Req

24、uest, discard the received packet and send Reset Request. These preceding actions are DTE specific error recovery actions. (d) Some of the tests given in this section may not be possible to carry out or may be inappropriate depending on the type of DTE. For instance some DTEs cannot handle Reset Ind

25、ication, some DTEs can handle Incoming Calls only, some DTEs cannot deal with a second restart sequence, etc. (e) In this case the testing laboratory should, with the aid of the questionnaire, carry out those tests which it considers appropriate. For all tests it is necessary that the Link Level is

26、in the Information Transfer Phase at the start of each of the tests in this section. (f) Unexpected behaviour of the DTE on Link Level may affect the Packet Level tests. (g) All packets sent by the DTE should conform with the format given in section 5 of CCITT Recommendation X.25 (1984) 11 and unles

27、s otherwise specified the contents of the fields in a packet sent by the tester are assumed to be correct. (h) The term “Discard” is used to indicate that the DTE ignores the received packet and takes no subsequent action as a direct result of receiving that packet, the DTE remains in the same state

28、. The test may be considered met if the DTE has not responded within a time equal to the DTEs declared TI. fi) Each test case is comprised of send and received packets. The state resulting from the transmission of a (k) All tests in this section are carried out with a Window size of 2 and a DTE must

29、 be able to implement a packet is enclosed in parenthesis. window size of 2 in order to comply with this section. 10.1 Restart In this section tests are described dealing with the Restart procedures. Test condition: The interface must be in state rl. IS : Restart Indication (r3) d VS: Restart Indica

30、tion (r3) Tester DTE Restart Confirmation (rl) Restart Confirmation (rl) - n- NET 2 15 - 7 7 Tests : Tester Expected behaviour from the DTE 10.1.1 Restart Indication (r3) . a Restart Confirmation (rl) 10.1.2 Restart Confirmation - t- Restart Request (r2) Restart Confirmation (rl) 10.1.3 Restart Conf

31、irmation A Restart Indication (r3) . t- Restart Request (r2) 10.2 State r.2 In this section tests are described while the interface is in state r2. Test condition: The interface must be in state r2. Tester DTE IS : Restart Indication (r3) A Restart Confirmation . VS: Restart Confirmation (rl) A Rest

32、art Indication (r3) L f- Restart Confirmation (rl) a Restart Request (r2) a Restart Confirmation (rl) Tests: Tester Expected behaviour from the DTE 10.2.1 Clear Indication - Discard (r2) 10.2.2 Clear Confirmation Discard (r2) 10.2.3 Incoming Call . Discard (r2) 10.2.4 Call Connected -+ Discard (r2)

33、10.2.5 Packet with PTI = 83 hex Discard (r2) CEPT NETU2 88 2326434 0000089 8 = 10.2.6 Restart Confirmation _+ GFI = 3 Discard (r2) 1) On an assigned LC. 10.3 Unnssigned Logical Chnnnels In this section tests are described dealing with unassigned logical channels. Test condition: The interface should

34、 be in state rl. Tester DTE IS : Restart Indication (r3) -+ VS: Restart Indication (r3) A a Restart Confirmation (rl) Restart Confirmation (rl) Tests: Tester Expected behaviour from the DTE 10.3.1 Incoming Call, on . 10.3.2 Clear Indication, on unassigned LC Discard unassigned LC Discard Tests 10.3.

35、1 and 10.3.2 should be carried out on logical channel group (lcg) numbers O and 1. Where a logical channel 1 has been assigned in lcg O but not in lcg 1 then logical channel 1 in Icg 1 should be tested, using 10.3.1 and 10.3.2. This also applies if vice versa. 16 NET 2 I - A F CEPT NET*2 AA m 232643

36、4 O000090 4 m 10.4 Statepl In this section tests are described while the interface is in state pl, but not dealing with the Call Set-up. Test condition: The LC should be in state pl. Tester IS: Clear Indication (p7) VS: Clear Indication (p7) Tests: Tester 10.4.1 Clear Indication (p7) 10.4.2 Call Con

37、nected Clear Confirmation (pi) 10.4.3 Clear Confirmation Clear Indication (pi) Packet with PTI = 83 hex Restart Indication (r3) 10.4.4 DTE Clear Confirmation (pi) Clear Confirmation (pi) Expected behaviour Note from the DTE Clear Confirmation (pi) 1) Clear Request (p6) Clear Request (p6) Clear Reque

38、st ($6) Restart Confirmation (rl) 1) DTE may also send Clear Request. 10.5 Incoming Call In this section tests dealing with Incoming Call packets are described. Test condition: The LC should be in state pl. Tester DTE IS: Clear Indication (p7) - Clear Confirmation (pi) Tests: Tester Expected behavio

39、ur from the DTE Note 10.5.1 Incoming Call, with Calling address - length = 6 (p3) L Call Accepted (p4) 1) 10.5.2 Incoming Call, with Calling address . length = 15, first digit = O (p3) Call Accepted (p4) 1) 10.5.3 Incoming Call with D-bit set to one (p3) Call Accepted (p4) DTE may send Clear Request

40、 if it does not support the D-bit procedure. 2) 10.5.4 Incoming Call, with some data in . the Call User Data Field (p3) Call Accepted (p4) 1) This Incoming Call should contain both the Calling Address and the Called Address. 2) The D-bit may be set to 1 or O in the Call Accepted packet, It may also

41、be necessary for the tester to meet specific requirements as defined by the DTE supplier. The DTEmay send “clear request” if these requirements are not met. NET 2 17 CEPT NET*Z 88 I 2326434 0000093 b I 10.6 Call Request number being in state pl. In this section tests dealing with Call Request packet

42、s are described. The DTE should use the LC with the highest Test condition: The LC should be in state pl. Tester DTE IS : Restart Indication (r3) . a Restart Confirmation (rl) VS: The aim of the VS in this section is to ensure that the DTE enters state p4, dl and this is the case if the DTE either s

43、ends a data packet or an RR packet. Some suggestions follow for verification sequences. The test house has to make a choice, depending on the characteristics of the DTE. Tester vs 1 VS2 Data Packet VS3 Data Packet Data Packet Tests: Tester DTE L Data Packet . L Data Packet or RR packet Data Packet o

44、r RR packet Expected behaviour from the DTE Note 10.6.1 Call Request with Called address length = 7 (32) Call Connected (p4) _, 10.6.2 Call Request with Called address length = 6 (p2) Call Connected (p4) . 10.6.3 L Call Request with Called address length = 15, first digit = O (p2) Call Connected (p4

45、) . 10.6.4 Call Request (p2) Call Connected, D-bit set to one (p4) DTE may send Clear Request in which case note 1 applies. If not, the LC should be in state p4. 10.6.5 Call Request (p2) Clear Indication (p7) . Clear Confirmation (pi) 1) 10.6.6 Call Request (p2) Restart Indication (r3) . Restart Con

46、firmation (rl) 1) 10.6.7 Call Request (p2) Clear Confirmation - Clear Request (p6) 10.6.8 L Call Request (p2) Packet with PTI = 83 hex . Clear Request (p6) 1) VS should not be done. CEPT NETx2 BB I 2326434 O000092 B m 10.7 Call Clearing In this section tests dealing with Call Clearing procedures are

47、 described. Test condition: The LC should be in state p4. Tester IS: Incoming Call 0-3) . Call Connected (p4) + VS1: Incoming Call (p3) * Call Connected (p4) - or L vs2 : L VS3 : Clear Confirmation Tests : followed by either VS1 or 2 Tester 10.7.1 Clear Indication (p7) - L 10.7.2 Packet - L Clear Co

48、nfirmation (pi) - 10.7.3 Packet L Clear Indication (pi) u 10.7.4 Packet . + - Restart Indication (r2) L 10.7.5 Packet Incoming Call . * 1) DTE may also send Clear Request. DTE Call Accepted (p4) Call Request 032) Call Accepted (p4) Call Request (p2) Expected behaviour Note from the DTE Clear Confirm

49、ation (pi) 1) 2) Clear Request (p6) Clear Request (p6) 2) Clear Request (p6) Restart Conrmation (rl) Clear Request (p6) 2) Discard (p6) 4) 2) 3) 4, VS3 should be done. 10.8 Call Collision Tester may send Incoming call or Call Connected or Clear Confirmation or use operator intervention in order to cause the DTE to answer with Clear Request. Either VSl or 2 should be done. In this section tests are executed while the LC is in state p5 (Call Collision). Test condition: The LC should be in state p5. IS : Tests: Tester Incoming Call (p5) -