Please enable JavaScript.
Coggle requires JavaScript to display documents.
NETWORK LAYER - Coggle Diagram
NETWORK LAYER
-
-
-
-
-
IP Characteristics
Connectionless
- Does not establish a connection with the destination before sending the packet.
- There is no control information needed (synchronizations, acknowledgments, etc.).
- The destination will receive the packet when it arrives, but no pre-notifications are sent by IP.
- If there is a need for connection-oriented traffic, then another protocol will handle this (typically TCP at the transport layer)
Best Effort Delivery
- No guarantees of delivery are made.
- Reduced overhead since there is no mechanism to resend data that is not received.
- Does not expect acknowledgments.
- Does not know if the other device is operational or if it received the packet.
Media Independent
Unreliable
- It cannot manage or fix undelivered or corrupt packets.
- IP cannot retransmit after an error.
- IP cannot realign out of sequence packets.
- IP must rely on other protocols for these functions.
Media independent
- IP does not concern itself with the type of frame required at the data link layer or the media type at the physical layer.
- IP can be sent over any media type: copper, fiber, or wireless.
-
Fragmentation
- Fragmenting causes latency.
- IPv6 does not fragment packets.
- Example: Router goes from Ethernet to a slow WAN with a smaller MTU
Routing
Types
Directly Connected – These routes are automatically added by the router, provided the interface is active and has addressing.
Remote – These are the routes the router does not have a direct connection and may be learned:
- Manually – with a static route
- Dynamically – by using a routing protocol to have the routers share their information with each other
Default Route – this forwards all traffic to a specific direction when there is not a match in the routing table
Static Routing
- Must be configured manually
- Must be adjusted manually by the administrator when there is a change in the topology
- Good for small non-redundant networks
- Often used in conjunction with a dynamic routing protocol for configuring a default route
Dynamic Routing
- Discover remote networks
- Maintain up-to-date information
- Choose the best path to the destination
- Find new best paths when there is a topology change
- Dynamic routing can also share static default routes with the other routers.
ARP
Basic Functions
- Resolving IPv4 addresses to MAC addresses
- Maintaining an ARP table of IPv4 to MAC address mappings
How Its Works
- If the packet’s destination IPv4 address is on the same network, the device will search the ARP table for the destination IPv4 address.
- If the destination IPv4 address is on a different network, the device will search the ARP table for the IPv4 address of the default gateway.
- If the device locates the IPv4 address, its corresponding MAC address is used as the destination MAC address in the frame.
- If there is no ARP table entry is found, then the device sends an ARP request.
-
-
-