fiona@excelan.com (Fiona Ho) (09/29/89)
Can anyone share with me the OSI protocol address format that you use in your OSI implementation ? Currently, I am working on an interface between session and transport. The protocol address format that I plan to use is as follows: |------|----------------|-------|---------------------| | L1 | TSAP | L2 | NSAP | |------|----------------|-------|---------------------| L1 one byte, specifies byte length of TSAP and must not exceed 32. L2 one byte, specifies byte length of NSAP and must not exceed 20. TSAP Transport service access point address. NSAP Network service access point address. Any information will be very much appreciated. Fiona Ho
michaud@devax.dec.com (Jeff Michaud) (09/29/89)
> |------|----------------|-------|---------------------| > | L1 | TSAP | L2 | NSAP | > |------|----------------|-------|---------------------| > > L1 one byte, specifies byte length of TSAP and must not exceed 32. > L2 one byte, specifies byte length of NSAP and must not exceed 20. > TSAP Transport service access point address. > NSAP Network service access point address. If I'm not mistaken, what you are calling a TSAP is really only a TSEL (Transport Selector). A TSAP includes the next lower layers addressing information (ie. TSAP would contain both the TSEL and the NSAP). Question, is 32 the max. TSEL length these days? I still hear rumblings that max. length may be increased (or is 32 the new length?)? /--------------------------------------------------------------\ |Jeff Michaud michaud@decwrl.dec.com michaud@decvax.dec.com| |DECnet-ULTRIX #include <standard/disclaimer.h> | \--------------------------------------------------------------/
sklower@ernie.Berkeley.EDU (Keith Sklower) (09/29/89)
In article <472@excelan.COM> fiona@excelan.com (Fiona Ho) writes: >Can anyone share with me the OSI protocol address format that you use in >your OSI implementation ? I'll apologize in advance for not drawing as neat diagrams as Fiona. (At the moment I'm working from home at 1200 baud). We plan to do something similar (here at Berkeley) except that we'll group all the lengths at the beginning so that you can easily locate the selectors via standard C constructs. Marshall Rose says that you must allow for 64 byte TSEL lengths. Also the 4.4BSD implementation will definitely allow for iso sockaddr's as big as you need; the 32byte structure shown here is a minimum. struct iso_addr { u_char isoa_len; /* length (in bytes) */ char isoa_genaddr[20]; /* general opaque address */ }; struct sockaddr_iso { u_char siso_len; /* total length */ u_char siso_family; /* family */ u_char siso_plen; /* presentation selector length */ u_char siso_slen; /* session selector length */ u_char siso_tlen; /* transport selector length */ struct iso_addr siso_addr; /* network address */ u_char siso_pad[6]; /* space for gosip v2 sels */ }; #define siso_nlen siso_addr.isoa_len #define siso_data siso_addr.isoa_genaddr #define TSEL(s) ((caddr_t)((s)->siso_data + (s)->siso_nlen)) #define SSEL(s) (TSEL(s) + (s)->siso_tlen) #define PSEL(s) (SSEL(s) + (s)->siso_slen)
REIJS@SURFNET.NL (10/04/89)
> > |------|----------------|-------|---------------------| > | L1 | TSAP | L2 | NSAP | > |------|----------------|-------|---------------------| > > L1 one byte, specifies byte length of TSAP and must not exceed 32. > L2 one byte, specifies byte length of NSAP and must not exceed 20. > TSAP Transport service access point address. > NSAP Network service access point address. > Some additional information. According X.213 Annex A, the nSAP can have a maximum length of 40 (decimal digits encoding of DSP) or 20 (binary octets encoding of DSP). In the RARE/COSINE community (Cooperation for Open Systems Interconnection networking in Europe) the decimal encoding is recommended, together with the use of NSAP ISO-DCC. In the same community RARE WG4 is now making a recommendation about how the allocation of NSAP ISO-DCC can be done by the National Standard Organizations. Further more a recommendation will be made, how the DSP will be allocated by the subnetworks. I hope you canb do something with the above information. All the best, _ _ _ _ |S| |U| |R| |F| ___________________________|___|___|___|_________________________ | | | (n) (e) (t) Victor Reijs tel: +31 30 310290 Network development fax: +31 30 340903 SURFnet b.v. E-mail: Reijs@surfnet.nl P.O.box 19035 3501 DA Utrecht The Netherlands