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As others have said, CCNA study materials are probably a good start. If you want to start understanding the point of of ASNs and BGP, this page isn't bad: http

As others have said, CCNA study materials are probably a good start. If you want to start understanding the point of of ASNs and BGP, this page isn't bad: https://www.cloudflare.com/en-gb/learning/network-layer/what-is-an-autonomous-system/ https://www.cloudflare.com/en-gb/learning/network-layer/what... Given what you've described about your task, you probably only need to learn TCP/IP, and don't need to learn about the lower layers (what the OSI model calls the physical and data link layer) or the upper ones (e.g. you probably don't care about whether your routers are carrying HTTP, SMTP or whatever). Internet: collection of LANs MAC address: the hardware address that uniquely identifies a network card, but is only visible to other devices on the same LAN IP address: an address that uniquely identifies a device on the internet Subnet: a subset of the IP address space, that's used for a LAN DHCP: the protocol routers use to assign an IP address to each device on the LAN ARP: the protocol used by a device on a LAN to find another device on the same LAN, when it knows the IP address but needs the MAC address. (You need the MAC address to send a packet to a device on your LAN) Router: has more than one network interface, with each interface on a different network. At home, your router is connected to your LAN, and to your ISPs network. ASN: A network that has a permanent allocation of part of the IP addr as space. BGP: the protocol used for one router to tell another router what networks it can route traffic to. How do you send traffic to devices when you aren't on the same LAN? You send them to your router (whose IP address you find out when you're assigned an IP address via DHCP, and whose MAC address you can find using ARP).

chousuke 5y ago
Nitpicking this a bit, IP addresses don't necessarily identify unique destination devices at all. They're just a label to help devices make a decision about packets they receive. IP addresses are more about the journey than the destination. To expand, I think it's crucial to understand that in order for an IP address to have any use at all, the device processing the packet must have additional configuration to know what to with it. Generally, devices either process packets locally, forward to other devices (possibly after modification), or discard them. This decision happens even at the end user's device, where you have a "default route" to a gateway device that then knows better. The default route is literally just a route that says "the entire internet is over here". Mail package analogies are common, but unlike physical mail, with IP packets it's no trouble to send copies of packets to multiple receivers (multicast, sometimes used to broadcast video streams) or to any receiver that happens to be closest to the user (anycast, common with DNS), or evenly distributed to any configured destination (load-balancing). IP networking is fundamentally pretty simple, but the simplicity gives you quite an array of options when you start to think about different mechanisms a router could employ to make routing decisions, especially if they communicate with other routers to share information about the networks they're connected to.
- rahimnathwani 5y ago
  Yes, definitely. This level of detail is what I hope OP will get from the CCNA books. But I think an approximate (if inaccurate) conceptual understanding is helpful for someone wanting to start doing stuff immediately.

chousuke 5y ago

Nitpicking this a bit, IP addresses don't necessarily identify unique destination devices at all. They're just a label to help devices make a decision about packets they receive. IP addresses are more about the journey than the destination. To expand, I think it's crucial to understand that in order for an IP address to have any use at all, the device processing the packet must have additional configuration to know what to with it. Generally, devices either process packets locally, forward to other devices (possibly after modification), or discard them. This decision happens even at the end user's device, where you have a "default route" to a gateway device that then knows better. The default route is literally just a route that says "the entire internet is over here". Mail package analogies are common, but unlike physical mail, with IP packets it's no trouble to send copies of packets to multiple receivers (multicast, sometimes used to broadcast video streams) or to any receiver that happens to be closest to the user (anycast, common with DNS), or evenly distributed to any configured destination (load-balancing). IP networking is fundamentally pretty simple, but the simplicity gives you quite an array of options when you start to think about different mechanisms a router could employ to make routing decisions, especially if they communicate with other routers to share information about the networks they're connected to.

rahimnathwani 5y ago
Yes, definitely. This level of detail is what I hope OP will get from the CCNA books. But I think an approximate (if inaccurate) conceptual understanding is helpful for someone wanting to start doing stuff immediately.