Vault sync: 2021-11-06 14:17:11

School/Analyse/Layers/3. Network Layer.md

@@ -23,3 +23,22 @@ Steps:
 A router can not practically store all hosts in the table as that would be way to many.
 
 So instead the router stores only possible destination networks.
+
+The address to identify a host on a networks should have the format:
+{Network, Host}
+
+## Forwarding
+
+When a router receives a packet:
+1. Extracts the destination address from packet.
+2. Separates the network ID from the rest of the address.
+3. Looks if it can match the networks id in routing table.
+4. If Match found: Sends packet using suggested paths in its table for that destination.
+5. If no match found: Send packet over the default path which is the path to the next (probably a higher level) router.
+
+### Separating network ID from address
+
+Router needs to know how many digits are used as network ID.
+Routers keep this information in their routing table.
+
+A binary number named a netmask