6 ms·

OSI is very widely used, most of the large ISPs use it. End consumers are just unaware of that fact. See https://en.wikipedia.org/wiki/IS-IS https://en.wikipedi

by betaby 2y ago

OSI is very widely used, most of the large ISPs use it. End consumers are just unaware of that fact. See https://en.wikipedia.org/wiki/IS-IS https://en.wikipedia.org/wiki/IS-IS

tialaramex 2y ago
I think this is a stretch, like saying the X.500 Directory System is widely used based on the fact that PKIX is technically adapting X.509 and thus your TLS certificates depend on the X.500 directory system. End users aren't just "unaware" that it's actually the X.500 system, it functionally isn't the X.500 system, PKIX mandates an "alternate" scheme for the Internet and the directory called for by X.500 has never actually existed. Likewise then, IS-IS is the protocol that OSI standardized, but we're not using as part of an OSI system.
- layer8 2y ago
  X.500 is widely used in the form of LDAP and Active Directory, however.
  - tristor 2y ago
    Active Directory is not based on X.500 and LDAP was directly created as an alternative to the DAP standard that is part of X.500. While X.500 is a precursor to both of these things, and influenced both of these things, and both of these things interoperated with X.500, they are not X.500. X.500 is for all intents and purposes pretty much dead in 2024, although I did deploy an X.500 based directory service in 2012 and it's probably still alive and running.
    - p_l 2y ago
      LDAP is just "lightweight" protocol for accessing an X.500 directory service. The semantics are the same for the accessed store, IIRC. The protocol definition explicitly talks about being used to access X.500 data stores as complementary interface to DAP (which requires lower layers of OSI stack vs LDAP's raw stream of bytes)
      - tristor 2y ago
        Yes, that is why it was invented, as I alluded to. LDAP was an alternative to DAP. DAP is part of the X.500 standard, LDAP is not. LDAP when it was first invented was built to access an X.500 directory. That is no longer a base requirement and most directories in the wild are not built on X.500. Standards mean things, just because LDAP was originally built to access X.500 doesn't mean it's part of X.500, and X.500 is a very detailed and specific standard which most directory services no longer follow.
        GauntletWizard 2y ago
        To reiterate in a slightly different form: Ldap is an inheritor of, and successor to, DAP/X.500, but not backwards compatible and only superficially resembling it at this point.
    - lukeh 2y ago
      Ironically there's probably more X.500 remnants in Active Directory than in the UMich-derived LDAP servers, thanks to its Exchange 5.5 legacy.
Hikikomori 2y ago
Would call it stretch to say it was widely used by ISPs. Some old ones may still be using integrated IS-IS as their IGP (early OSPF had scaling issues and complicated solutions for that), but that's nothing like widely using the ISO stack. But they might have used IS-IS it to route NSAP in their network at some point in time to manage ATM-era equipment, the ISP I worked still had some ctunnels for that purpose, I doubt they still have them.
- p_l 2y ago
  It was still widely used for IPv4 and v6 in 2000s. ex telco engineer told us that two major reasons was that IS-IS was simply more efficient, and that they didn't require IP communication between routers - meaning troubleshooting and management was easier than providing p2p routes for IP-based protocols.
  - Hikikomori 2y ago
    It's still widely used, among old ISPs because why switch when it's just as good or better than the alternative and your engineers know it best. But it's not the whole stack as implied in the first reply. It was popular primarily because OSPF didn't scale well with hundreds to thousands of routers with the minimal CPU power even large core routers had.
    - p_l 2y ago
      Scalability was one part. Later the fact that you didn't need separate routing setup for v6 also was part of it. But for a telco, the fact that you didn't have to setup IP connectivity in order for routers to see each other, was also a crucial ability.
      - Hikikomori 2y ago
        OSPF has supported unnumbered links for a long time, don't need IP on the link with point to point and multicast.

by betaby 2y ago

OSI is very widely used, most of the large ISPs use it. End consumers are just unaware of that fact. See https://en.wikipedia.org/wiki/IS-IS https://en.wikipedia.org/wiki/IS-IS

tialaramex 2y ago

I think this is a stretch, like saying the X.500 Directory System is widely used based on the fact that PKIX is technically adapting X.509 and thus your TLS certificates depend on the X.500 directory system. End users aren't just "unaware" that it's actually the X.500 system, it functionally isn't the X.500 system, PKIX mandates an "alternate" scheme for the Internet and the directory called for by X.500 has never actually existed. Likewise then, IS-IS is the protocol that OSI standardized, but we're not using as part of an OSI system.

layer8 2y ago
X.500 is widely used in the form of LDAP and Active Directory, however.
- tristor 2y ago
  Active Directory is not based on X.500 and LDAP was directly created as an alternative to the DAP standard that is part of X.500. While X.500 is a precursor to both of these things, and influenced both of these things, and both of these things interoperated with X.500, they are not X.500. X.500 is for all intents and purposes pretty much dead in 2024, although I did deploy an X.500 based directory service in 2012 and it's probably still alive and running.
  - p_l 2y ago
    LDAP is just "lightweight" protocol for accessing an X.500 directory service. The semantics are the same for the accessed store, IIRC. The protocol definition explicitly talks about being used to access X.500 data stores as complementary interface to DAP (which requires lower layers of OSI stack vs LDAP's raw stream of bytes)
    - tristor 2y ago
      Yes, that is why it was invented, as I alluded to. LDAP was an alternative to DAP. DAP is part of the X.500 standard, LDAP is not. LDAP when it was first invented was built to access an X.500 directory. That is no longer a base requirement and most directories in the wild are not built on X.500. Standards mean things, just because LDAP was originally built to access X.500 doesn't mean it's part of X.500, and X.500 is a very detailed and specific standard which most directory services no longer follow.
      - GauntletWizard 2y ago
        To reiterate in a slightly different form: Ldap is an inheritor of, and successor to, DAP/X.500, but not backwards compatible and only superficially resembling it at this point.
  - lukeh 2y ago
    Ironically there's probably more X.500 remnants in Active Directory than in the UMich-derived LDAP servers, thanks to its Exchange 5.5 legacy.

Hikikomori 2y ago

Would call it stretch to say it was widely used by ISPs. Some old ones may still be using integrated IS-IS as their IGP (early OSPF had scaling issues and complicated solutions for that), but that's nothing like widely using the ISO stack. But they might have used IS-IS it to route NSAP in their network at some point in time to manage ATM-era equipment, the ISP I worked still had some ctunnels for that purpose, I doubt they still have them.

p_l 2y ago
It was still widely used for IPv4 and v6 in 2000s. ex telco engineer told us that two major reasons was that IS-IS was simply more efficient, and that they didn't require IP communication between routers - meaning troubleshooting and management was easier than providing p2p routes for IP-based protocols.
- Hikikomori 2y ago
  It's still widely used, among old ISPs because why switch when it's just as good or better than the alternative and your engineers know it best. But it's not the whole stack as implied in the first reply. It was popular primarily because OSPF didn't scale well with hundreds to thousands of routers with the minimal CPU power even large core routers had.
  - p_l 2y ago
    Scalability was one part. Later the fact that you didn't need separate routing setup for v6 also was part of it. But for a telco, the fact that you didn't have to setup IP connectivity in order for routers to see each other, was also a crucial ability.
    - Hikikomori 2y ago
      OSPF has supported unnumbered links for a long time, don't need IP on the link with point to point and multicast.