6 ms·

Is it just me or BGP is something I never learnt about until I heard about it causing issues? It seems it's essential to the internet, just like TCP/IP, but nev

by dakiol 1y ago

Is it just me or BGP is something I never learnt about until I heard about it causing issues? It seems it's essential to the internet, just like TCP/IP, but nevertheless I learnt about the latter in the university, during my career, I read many books about TCP/IP... but nothing about BGP (not in the university, not at work, not in books, nothing). I can "play" with TCP/IP at home in dummy projects and learn more about it... but I have no idea how to "play" with BGP. In that regard, how does one learn about it at home?

klysm 1y ago
It’s very much hidden, which I guess is a success of the design. You need not concern yourself with the web of ASNs when using IP.
altilunium 1y ago
I think you need to manage a real (and large) network that's connected to global internet traffic in order to "play" with BGP. Well, you can tinker with it at home, but only by using a network simulator.
- bc569a80a344f9c 1y ago
  You can set up local BGP routers and peer them and play with it. Another fun thing is to log into publicly available looking glass servers. Most ISPs (including very, very, very large ones) operate routers that have their full view of the BGP routing tables. They either run web interfaces that let you query those tables (more common) or make public ssh or telnet credentials to log in with roles that have very limited access to the available commands, but have read rights to those tables.
  - _gmax0 1y ago
    Internet researchers commonly use RIPE and RouteViews. https://www.routeviews.org/routeviews/about/ https://www.routeviews.org/routeviews/about/ https://stat.ripe.net/docs/02.data-api/ https://stat.ripe.net/docs/02.data-api/
- ta1243 1y ago
  I've used BGP internally at my company for a decade, using AS65xxx range. At home I use BGP between the house, garage and shed, I much prefer it to OSPF.
  - normie3000 1y ago
    Should we know what OSPF is too?
    - icedchai 1y ago
      Unless you're heavily into networking and the ISP space, there's basically no need for you to know about routing protocols.
    - pixl97 1y ago
      Depends if you do any routing on multipath networks. Most people don't so there's that.
      - Hikikomori 1y ago
        ECMP? Can do that with static routes. As long as you have more than 1 router you could set up a routing protocol. Or did you mean multipoint?
    - unethical_ban 1y ago
      Open Shortest Path First (OSPF) is an "internal" routing protocol. Basically, it is a protocol for routers to share routes when all routers are managed by the same organization. Border Gateway Protocol (BGP) has the primary purpose of sharing routes between routers managed by different organizations. It can be used within an organization too. It has a lot more control over how and which routes it sends and receives.
    - ta1243 1y ago
      Depends how much you want to know about how networks work. Never ceases to amaze me how ignorant modern software developers are of the underlying technology, I guess that's because I'm from the pre-2010s when "Information Technology" was a general field.
- buzer 1y ago
  On top of the already suggested local BGP routers you can also use https://dn42.us/ https://dn42.us/ to test a bit more real-world like scenarios.
- icedchai 1y ago
  It doesn't have to be that large. Many people have "personal" ASNs. Check out this blog (not me, I just remember it from years back): https://blog.thelifeofkenneth.com/2017/11/creating-autonomous-system-for-fun-and.html https://blog.thelifeofkenneth.com/2017/11/creating-autonomou...
  - azinman2 1y ago
    Really interesting post! Thanks for sharing
  - Orochikaku 1y ago
    The author spoke about this story on my favourite podcast, On The Metal (of Oxide Computer Company) https://onthemetal.transistor.fm/episodes/kenneth-finnegan https://onthemetal.transistor.fm/episodes/kenneth-finnegan
  - wildzzz 1y ago
    I worked an internship where I spent the summer setting up new equipment for a large corp that was replacing everything that AT&T had installed and managed with their own stuff. Nearly every office had their own ASN, everyone else got regular broadband or just a box of aircards depending on the number of users. I knew nothing about networks other than setting up my own consumer router at home so it was a pretty fun learning experience. I always got a smile on my face when I finally got vRouter to peer with our dummy AS in the office then we'd pack it all up and bring it out for installation over the weekend. I got offered a job to come back after I graduated but turned it down for something that paid better and was a lot more interesting. Honestly, I probably would be making more money as a network engineer now if I stuck with it.
    - heraldgeezer 1y ago
      The world is kinda screaming for experienced networking engineers ye
- Bluecobra 1y ago
  You don’t need a large network to participate to BGP. You just need a /24 (IPv4) or /48 (IPv6) allocation, AS number, and a business class Internet connection that can do BGP. Might be out of reach for most hobbyists but not impossible.
  - icedchai 1y ago
    You don't even need a business class connection. You can do BGP over a tunnel to a VPS or colo.
- Hikikomori 1y ago
  Not really, you can learn it just fine with simulators and a few routers. Designing and operating BGP in a large network is another thing though.
bc569a80a344f9c 1y ago
Buy some routers that have BGP implementations (there are some cheap ones, Mikrotik for example), or use open source implementations. The article lists bird, another very popular one is FRR (free range routing). You can trivially stand up two docker containers, stand up a BGP session between them, and - for example - propagate static routes you set up within them. If you like guided tutorials, https://blog.ipspace.net/2023/08/bgp-labs-basic-setup/ https://blog.ipspace.net/2023/08/bgp-labs-basic-setup/ is rather good and has been extended to somewhat advanced topics. Everything needed to follow along is free software.
- remram 1y ago
  A good tool to try this stuff is containerlab: https://containerlab.dev/ https://containerlab.dev/ It lets you setup multiple containers with direct connections between them in whatever topology you want. It allows you to run both Linux containers (with FRR for example) and emulated versions of popular router platforms (some of the ones mentioned in the article).
- SoftTalker 1y ago
  OpenBSD include bgpd(8) out of the box: DESCRIPTION bgpd is a Border Gateway Protocol (BGP) daemon which manages the network routing tables. Its main purpose is to exchange information concerning "network reachability" with other BGP systems. bgpd uses the Border Gateway Protocol, Version 4, as described in RFC 4271.
  - petee 1y ago
    And a looking glass interface ready to go
- zokier 1y ago
  At least to me one of the challenges is relating to the problems that BGP solves. You can get pretty far in network complexity before BGP (or OSPF etc) really does anything for you. What would be good scenarios one could encounter in "homelab" situation where BGP would be beneficial?
pixl97 1y ago
So back when I did Wisp stuff I'd set up simulates networks between multiple machines with real and virtual networks. VyOS which was similar to the UBNT equipment we were using is light weight and supports multiple protocols.
kalaksi 1y ago
Well, what did you study in the university? I did learn about BGP and routing in university since one of my subjects was information networks and protocols. But haven't really used it outside of some lab exercises since there's been no need at work nor at home.
ecshafer 1y ago
My undergraduate networking course didn't touch BGP, my graduate networking course did touch BGP. We used a python package that acted as a simulator for different AS but I can't remember which one.
acc_297 1y ago
My undergrad networks course discussed a little BGP stuff but only on the blackboard. To experiment with BGP you could use a network simulator like what the author of this blog did. In my class we used something called gini[1] which I think my profs grad student wrote but the author apparently used gns3 which seems to be a cisco specific ns3 version. I used ns3 once and found it had a steep learning curve. The gini simulator has a more basic user interface but is probably less powerful. [1] https://citelab.github.io/gini5/ https://citelab.github.io/gini5/ [2] https://docs.gns3.com/docs/ https://docs.gns3.com/docs/
mfro 1y ago
DN42[1] provides a playground for routing technologies. I wouldn't recommend digging in if you don't want to dedicate a lot of time into it. As someone fairly well versed in networking, WAN routing is still confusing to me. GNS3 is probably the easiest way to get hands on experience with any networking technologies. [1]: https://wiki.dn42.us/home https://wiki.dn42.us/home
unethical_ban 1y ago
TCP/IP affects every networked application and endpoint on the internet. BGP runs the internet routing "in the background" and you only need to know it if you're an internet service provider or work in a large org managing the network. If you didn't learn network routing, you aren't going to learn BGP. Put two or three VMs (OpenBSD has OpenBGPD daemon) onto a shared virtual switch and addresses in 172.31.255.0/24, connect the VMs. Also each of the VMs should have at least one other interface onto unique virtual switches with their own network (172.31.1.0/24, 172.31.2.0/24, etc). Then set up BGP to redistribute connected routes.
ajsnigrutin 1y ago
BPG is like international shipping... it has to be there for the world to function, but most people don't need to interact with it. One way to play with it is something like this: https://www.eve-ng.net/ https://www.eve-ng.net/ The other is to make a couple of virtual machines with a couple of network interfaces, make some sort of network betweeen them and then use some bgp routing deamon, eg: https://bird.network.cz/ https://bird.network.cz/ https://www.nongnu.org/quagga/ https://www.nongnu.org/quagga/ etc.
elij 1y ago
if you're a linux person consider a routing on host setup with FRR with /32s. As every host is a /32 network you can focus more on the aspects of BGP rather than TCP/IP.
mzsl 1y ago
In my opinion, containerlab is one of the easier tools to setup a lab environment for networking. You define a network with yaml which consists of nodes and links between them and it creates these using docker. They also have a BGP peering example lab: https://containerlab.dev/lab-examples/peering-lab/ https://containerlab.dev/lab-examples/peering-lab/
toast0 1y ago
When has BGP not been implicated in causing issues though? The first widespread incident I found was from 1997 [1], but I didn't look too hard. I don't think there's really a satisfying way to play with BGP as a small network. Traffic engineering is where I think the fun would be, but you've got to have lots of traffic and many connections for it to be worthwhile. Then you'd be trying to use your announcements to coax the rest of the internet to push packets through the connections you want. As well as perhaps adjusting your outgoing packets to travel the connections you prefer when possible. Sadly, nobody lets me play with their setup. One of the ways to get a sense of emergent routing behavior is if you have hosting in many places, you'll likely see a lot of differences in routes when you start going to far off countries. If you run traceroutes (or mtr) from your home internet and your cell phone and various hosting, and if you can trace back... you'll likely see a diversity of routes. Sometimes you'll see things like going from west coast US to Brazil, where one ISP will send your packets to florida, then Brazil, and one ISP will send your packets to Spain, then Brazil, with a lot more latency. [1] https://en.m.wikipedia.org/wiki/AS_7007_incident https://en.m.wikipedia.org/wiki/AS_7007_incident
- immibis 1y ago
  You can play with BGP by joining https://dn42.eu/ https://dn42.eu/ - a fake internet with a few thousand participants who are mostly as clueless as you, and none of whom will lose millions of dollars per hour if it breaks (which is not infrequently).
- moefh 1y ago
  I still remember when Pakistan accidentally shut down YouTube in the entire world for about 2 hours in 2008: https://www.cnet.com/culture/how-pakistan-knocked-youtube-offline-and-how-to-make-sure-it-never-happens-again/ https://www.cnet.com/culture/how-pakistan-knocked-youtube-of...
nikanj 1y ago
I remember Helsinki CS having quite a bit of BGP, TCP and both ipv4 and ipv6. No guarantees that every student aced those classes, but the teaching definitely was there
- heraldgeezer 1y ago
  I mean the birthplace of Nokia would have it ofc ;) /Live in Ericsson lands
protocolture 1y ago
Its hard to get real hands on BGP experience. A lab wont ever reflect the complexity of a carrier environment. That said, just bang a couple of mikrotiks together if you want to play with it.
- AStonesThrow 1y ago
  True indeed, true indeed. Cisco offers some simulator tooling. It basically virtualizes a lot of networking devices and allows you to play LEGO/SimCity with them: Cisco Packet Tracer https://www.netacad.com/learning-collections/cisco-packet-tracer?courseLang=en-US https://www.netacad.com/learning-collections/cisco-packet-tr... Now, we built toy networks from scratch while I was working toward my certification. Surely larger-scale simulation files could be loaded into Packet Tracer. And perhaps, vendors have simulators on a larger scale than the free downloads? https://developer.cisco.com/modeling-labs/ https://developer.cisco.com/modeling-labs/ When I worked at a regional ISP, my supervisor was the BGP wizard. He referred to exterior routing as "a black art". Even more, the telcos were deploying their own technologies like Frame Relay and SMDS, which are Layer 1/Layer 2 protocols beyond the standard "point-to-point" leased lines. We once experienced a fiber cut on our T-3 backbone (construction workers didn't dial 811). So my supervisor arranged the BGP routes to send everything over a 56k line, IIRC. He gloated about it. The packet loss rate was absurd, but our customers had connectivity!
  - protocolture 1y ago
    >When I worked at a regional ISP, my supervisor was the BGP wizard. He referred to exterior routing as "a black art". Yep this seems like a very common experience. I tend to find most environments have one guy making BGP changes outside of project work. >We once experienced a fiber cut on our T-3 backbone (construction workers didn't dial 811). So my supervisor arranged the BGP routes to send everything over a 56k line, IIRC. He gloated about it. The packet loss rate was absurd, but our customers had connectivity! The modern version of this: At a small national ISP, we had our intercarrier lines cut. Megaport has this billing model where you only pay for the capacity you use, so our backup intercapital was a 1MB megaport service. Intercapital goes down, everyone kicks over to the megaport and we just log on to the megaport portal and raise the bandwidth to a few gig temporarily. Cost almost nothing to keep it sitting there ready for use. And yeah the engineer responsible was extremely and deservedly smug. >And perhaps, vendors have simulators on a larger scale than the free downloads? My experience is that you need both the exact hardware/firmware AND the exact config to perfectly simulate some of the weird and wonderful stuff. Largely because so much of the protocols issues, like the OP suggests, is down to individual vendor implementations of the protocol. For instance, I used to consult for a small ISP that had a very unreliable peer. That peer would send them routes for everything, but occasionally their PE's routing plane would collapse and stop forwarding traffic to/from their other peers. We still received enough packets to not trip any failover, and routes were still being advertised. So until they realised and rebooted their hardware, we had to withdraw our routes. This is the specific behaviour between (IIRC) Cisco IOS-XR on our end, their predominantly mikrotik environment, and their other peers who I believe were mostly juniper. I cant imagine simulating that without the relevant hardware and configs.
franga2000 1y ago
I learned (and later taught) BGP (and routing in general), albeit at a superficial level, in high school already. Then I actually got to work with it during labs in university.
heraldgeezer 1y ago
CCNA has BGP now and that was part of my college curriculum. It depends on what you study. I did more of a sysadmin track, you (probably?) did comp sci/dev and would not encounter BPG in a dev job (probably).

by dakiol 1y ago

klysm 1y ago

It’s very much hidden, which I guess is a success of the design. You need not concern yourself with the web of ASNs when using IP.

altilunium 1y ago

I think you need to manage a real (and large) network that's connected to global internet traffic in order to "play" with BGP. Well, you can tinker with it at home, but only by using a network simulator.

bc569a80a344f9c 1y ago
You can set up local BGP routers and peer them and play with it. Another fun thing is to log into publicly available looking glass servers. Most ISPs (including very, very, very large ones) operate routers that have their full view of the BGP routing tables. They either run web interfaces that let you query those tables (more common) or make public ssh or telnet credentials to log in with roles that have very limited access to the available commands, but have read rights to those tables.
- _gmax0 1y ago
  Internet researchers commonly use RIPE and RouteViews. https://www.routeviews.org/routeviews/about/ https://www.routeviews.org/routeviews/about/ https://stat.ripe.net/docs/02.data-api/ https://stat.ripe.net/docs/02.data-api/
ta1243 1y ago
I've used BGP internally at my company for a decade, using AS65xxx range. At home I use BGP between the house, garage and shed, I much prefer it to OSPF.
- normie3000 1y ago
  Should we know what OSPF is too?
  - icedchai 1y ago
    Unless you're heavily into networking and the ISP space, there's basically no need for you to know about routing protocols.
  - pixl97 1y ago
    Depends if you do any routing on multipath networks. Most people don't so there's that.
    - Hikikomori 1y ago
      ECMP? Can do that with static routes. As long as you have more than 1 router you could set up a routing protocol. Or did you mean multipoint?
  - unethical_ban 1y ago
    Open Shortest Path First (OSPF) is an "internal" routing protocol. Basically, it is a protocol for routers to share routes when all routers are managed by the same organization. Border Gateway Protocol (BGP) has the primary purpose of sharing routes between routers managed by different organizations. It can be used within an organization too. It has a lot more control over how and which routes it sends and receives.
  - ta1243 1y ago
    Depends how much you want to know about how networks work. Never ceases to amaze me how ignorant modern software developers are of the underlying technology, I guess that's because I'm from the pre-2010s when "Information Technology" was a general field.
buzer 1y ago
On top of the already suggested local BGP routers you can also use https://dn42.us/ https://dn42.us/ to test a bit more real-world like scenarios.
icedchai 1y ago
It doesn't have to be that large. Many people have "personal" ASNs. Check out this blog (not me, I just remember it from years back): https://blog.thelifeofkenneth.com/2017/11/creating-autonomous-system-for-fun-and.html https://blog.thelifeofkenneth.com/2017/11/creating-autonomou...
- azinman2 1y ago
  Really interesting post! Thanks for sharing
- Orochikaku 1y ago
  The author spoke about this story on my favourite podcast, On The Metal (of Oxide Computer Company) https://onthemetal.transistor.fm/episodes/kenneth-finnegan https://onthemetal.transistor.fm/episodes/kenneth-finnegan
- wildzzz 1y ago
  I worked an internship where I spent the summer setting up new equipment for a large corp that was replacing everything that AT&T had installed and managed with their own stuff. Nearly every office had their own ASN, everyone else got regular broadband or just a box of aircards depending on the number of users. I knew nothing about networks other than setting up my own consumer router at home so it was a pretty fun learning experience. I always got a smile on my face when I finally got vRouter to peer with our dummy AS in the office then we'd pack it all up and bring it out for installation over the weekend. I got offered a job to come back after I graduated but turned it down for something that paid better and was a lot more interesting. Honestly, I probably would be making more money as a network engineer now if I stuck with it.
  - heraldgeezer 1y ago
    The world is kinda screaming for experienced networking engineers ye
Bluecobra 1y ago
You don’t need a large network to participate to BGP. You just need a /24 (IPv4) or /48 (IPv6) allocation, AS number, and a business class Internet connection that can do BGP. Might be out of reach for most hobbyists but not impossible.
- icedchai 1y ago
  You don't even need a business class connection. You can do BGP over a tunnel to a VPS or colo.
Hikikomori 1y ago
Not really, you can learn it just fine with simulators and a few routers. Designing and operating BGP in a large network is another thing though.

bc569a80a344f9c 1y ago

Buy some routers that have BGP implementations (there are some cheap ones, Mikrotik for example), or use open source implementations. The article lists bird, another very popular one is FRR (free range routing). You can trivially stand up two docker containers, stand up a BGP session between them, and - for example - propagate static routes you set up within them. If you like guided tutorials, https://blog.ipspace.net/2023/08/bgp-labs-basic-setup/ https://blog.ipspace.net/2023/08/bgp-labs-basic-setup/ is rather good and has been extended to somewhat advanced topics. Everything needed to follow along is free software.

remram 1y ago
A good tool to try this stuff is containerlab: https://containerlab.dev/ https://containerlab.dev/ It lets you setup multiple containers with direct connections between them in whatever topology you want. It allows you to run both Linux containers (with FRR for example) and emulated versions of popular router platforms (some of the ones mentioned in the article).
SoftTalker 1y ago
OpenBSD include bgpd(8) out of the box: DESCRIPTION bgpd is a Border Gateway Protocol (BGP) daemon which manages the network routing tables. Its main purpose is to exchange information concerning "network reachability" with other BGP systems. bgpd uses the Border Gateway Protocol, Version 4, as described in RFC 4271.
- petee 1y ago
  And a looking glass interface ready to go
zokier 1y ago
At least to me one of the challenges is relating to the problems that BGP solves. You can get pretty far in network complexity before BGP (or OSPF etc) really does anything for you. What would be good scenarios one could encounter in "homelab" situation where BGP would be beneficial?

pixl97 1y ago

So back when I did Wisp stuff I'd set up simulates networks between multiple machines with real and virtual networks. VyOS which was similar to the UBNT equipment we were using is light weight and supports multiple protocols.

kalaksi 1y ago

Well, what did you study in the university? I did learn about BGP and routing in university since one of my subjects was information networks and protocols. But haven't really used it outside of some lab exercises since there's been no need at work nor at home.

ecshafer 1y ago

My undergraduate networking course didn't touch BGP, my graduate networking course did touch BGP. We used a python package that acted as a simulator for different AS but I can't remember which one.

acc_297 1y ago

My undergrad networks course discussed a little BGP stuff but only on the blackboard. To experiment with BGP you could use a network simulator like what the author of this blog did. In my class we used something called gini[1] which I think my profs grad student wrote but the author apparently used gns3 which seems to be a cisco specific ns3 version. I used ns3 once and found it had a steep learning curve. The gini simulator has a more basic user interface but is probably less powerful. [1] https://citelab.github.io/gini5/ https://citelab.github.io/gini5/ [2] https://docs.gns3.com/docs/ https://docs.gns3.com/docs/

mfro 1y ago

DN42[1] provides a playground for routing technologies. I wouldn't recommend digging in if you don't want to dedicate a lot of time into it. As someone fairly well versed in networking, WAN routing is still confusing to me. GNS3 is probably the easiest way to get hands on experience with any networking technologies. [1]: https://wiki.dn42.us/home https://wiki.dn42.us/home

unethical_ban 1y ago

TCP/IP affects every networked application and endpoint on the internet. BGP runs the internet routing "in the background" and you only need to know it if you're an internet service provider or work in a large org managing the network. If you didn't learn network routing, you aren't going to learn BGP. Put two or three VMs (OpenBSD has OpenBGPD daemon) onto a shared virtual switch and addresses in 172.31.255.0/24, connect the VMs. Also each of the VMs should have at least one other interface onto unique virtual switches with their own network (172.31.1.0/24, 172.31.2.0/24, etc). Then set up BGP to redistribute connected routes.

ajsnigrutin 1y ago

BPG is like international shipping... it has to be there for the world to function, but most people don't need to interact with it. One way to play with it is something like this: https://www.eve-ng.net/ https://www.eve-ng.net/ The other is to make a couple of virtual machines with a couple of network interfaces, make some sort of network betweeen them and then use some bgp routing deamon, eg: https://bird.network.cz/ https://bird.network.cz/ https://www.nongnu.org/quagga/ https://www.nongnu.org/quagga/ etc.

elij 1y ago

if you're a linux person consider a routing on host setup with FRR with /32s. As every host is a /32 network you can focus more on the aspects of BGP rather than TCP/IP.

mzsl 1y ago

In my opinion, containerlab is one of the easier tools to setup a lab environment for networking. You define a network with yaml which consists of nodes and links between them and it creates these using docker. They also have a BGP peering example lab: https://containerlab.dev/lab-examples/peering-lab/ https://containerlab.dev/lab-examples/peering-lab/

toast0 1y ago

When has BGP not been implicated in causing issues though? The first widespread incident I found was from 1997 [1], but I didn't look too hard. I don't think there's really a satisfying way to play with BGP as a small network. Traffic engineering is where I think the fun would be, but you've got to have lots of traffic and many connections for it to be worthwhile. Then you'd be trying to use your announcements to coax the rest of the internet to push packets through the connections you want. As well as perhaps adjusting your outgoing packets to travel the connections you prefer when possible. Sadly, nobody lets me play with their setup. One of the ways to get a sense of emergent routing behavior is if you have hosting in many places, you'll likely see a lot of differences in routes when you start going to far off countries. If you run traceroutes (or mtr) from your home internet and your cell phone and various hosting, and if you can trace back... you'll likely see a diversity of routes. Sometimes you'll see things like going from west coast US to Brazil, where one ISP will send your packets to florida, then Brazil, and one ISP will send your packets to Spain, then Brazil, with a lot more latency. [1] https://en.m.wikipedia.org/wiki/AS_7007_incident https://en.m.wikipedia.org/wiki/AS_7007_incident

immibis 1y ago
You can play with BGP by joining https://dn42.eu/ https://dn42.eu/ - a fake internet with a few thousand participants who are mostly as clueless as you, and none of whom will lose millions of dollars per hour if it breaks (which is not infrequently).
moefh 1y ago
I still remember when Pakistan accidentally shut down YouTube in the entire world for about 2 hours in 2008: https://www.cnet.com/culture/how-pakistan-knocked-youtube-offline-and-how-to-make-sure-it-never-happens-again/ https://www.cnet.com/culture/how-pakistan-knocked-youtube-of...

nikanj 1y ago

I remember Helsinki CS having quite a bit of BGP, TCP and both ipv4 and ipv6. No guarantees that every student aced those classes, but the teaching definitely was there

heraldgeezer 1y ago
I mean the birthplace of Nokia would have it ofc ;) /Live in Ericsson lands

protocolture 1y ago

Its hard to get real hands on BGP experience. A lab wont ever reflect the complexity of a carrier environment. That said, just bang a couple of mikrotiks together if you want to play with it.

AStonesThrow 1y ago
True indeed, true indeed. Cisco offers some simulator tooling. It basically virtualizes a lot of networking devices and allows you to play LEGO/SimCity with them: Cisco Packet Tracer https://www.netacad.com/learning-collections/cisco-packet-tracer?courseLang=en-US https://www.netacad.com/learning-collections/cisco-packet-tr... Now, we built toy networks from scratch while I was working toward my certification. Surely larger-scale simulation files could be loaded into Packet Tracer. And perhaps, vendors have simulators on a larger scale than the free downloads? https://developer.cisco.com/modeling-labs/ https://developer.cisco.com/modeling-labs/ When I worked at a regional ISP, my supervisor was the BGP wizard. He referred to exterior routing as "a black art". Even more, the telcos were deploying their own technologies like Frame Relay and SMDS, which are Layer 1/Layer 2 protocols beyond the standard "point-to-point" leased lines. We once experienced a fiber cut on our T-3 backbone (construction workers didn't dial 811). So my supervisor arranged the BGP routes to send everything over a 56k line, IIRC. He gloated about it. The packet loss rate was absurd, but our customers had connectivity!
- protocolture 1y ago
  >When I worked at a regional ISP, my supervisor was the BGP wizard. He referred to exterior routing as "a black art". Yep this seems like a very common experience. I tend to find most environments have one guy making BGP changes outside of project work. >We once experienced a fiber cut on our T-3 backbone (construction workers didn't dial 811). So my supervisor arranged the BGP routes to send everything over a 56k line, IIRC. He gloated about it. The packet loss rate was absurd, but our customers had connectivity! The modern version of this: At a small national ISP, we had our intercarrier lines cut. Megaport has this billing model where you only pay for the capacity you use, so our backup intercapital was a 1MB megaport service. Intercapital goes down, everyone kicks over to the megaport and we just log on to the megaport portal and raise the bandwidth to a few gig temporarily. Cost almost nothing to keep it sitting there ready for use. And yeah the engineer responsible was extremely and deservedly smug. >And perhaps, vendors have simulators on a larger scale than the free downloads? My experience is that you need both the exact hardware/firmware AND the exact config to perfectly simulate some of the weird and wonderful stuff. Largely because so much of the protocols issues, like the OP suggests, is down to individual vendor implementations of the protocol. For instance, I used to consult for a small ISP that had a very unreliable peer. That peer would send them routes for everything, but occasionally their PE's routing plane would collapse and stop forwarding traffic to/from their other peers. We still received enough packets to not trip any failover, and routes were still being advertised. So until they realised and rebooted their hardware, we had to withdraw our routes. This is the specific behaviour between (IIRC) Cisco IOS-XR on our end, their predominantly mikrotik environment, and their other peers who I believe were mostly juniper. I cant imagine simulating that without the relevant hardware and configs.

franga2000 1y ago

I learned (and later taught) BGP (and routing in general), albeit at a superficial level, in high school already. Then I actually got to work with it during labs in university.

heraldgeezer 1y ago

CCNA has BGP now and that was part of my college curriculum. It depends on what you study. I did more of a sysadmin track, you (probably?) did comp sci/dev and would not encounter BPG in a dev job (probably).