COMP1055 Lecture 13: Routing and IP Study Notes

Reliability of Internet Protocol (IP)

IP is a best-effort protocol, which means it delivers datagrams without guaranteeing that they will arrive, remain in order, or be free of duplicates.

Benefits of Best-Effort Delivery

Minimizes network overhead and increases speed for real-time applications by removing the need for acknowledgments or retransmissions at the IP layer.

Limitations of Best-Effort Delivery

The protocol is inherently unreliable; reliability, ordering, and data integrity must be managed by higher-layer protocols like TCP.

Benefits of CIDR Aggregation

Enables route summarization, allowing one routing table entry to represent multiple networks, which reduces processing and memory demands on routers.

Benefits of IPv6 Efficiency

Features a simplified header format that allows for faster processing by routers compared to the more complex IPv4 header.

Limitations of IPv6 Transition

Lacks backward-compatibility with IPv4 and introduces management complexity due to the length of 128-bit addresses.

Benefit of Store-and-Forward Mechanism

Ensures that a packet is fully received and undergoes error checking before being forwarded to the next network link.

Limitation of Store-and-Forward Mechanism

Increases overall network latency because the entire packet must be buffered before forwarding can begin.

Benefit of Source Independence

Simplifies routing logic by ensuring routers only need to determine the next hop based on the destination address, regardless of the packet's origin.

Limitation of Source Independence

Makes advanced security filtering or traffic engineering (such as preventing IP spoofing) more difficult for routers to perform.

Packet Forwarding

The process of moving data packets from one network to another until they reach their destination, involving multiple layers of the networking stack.

Internet Protocol (IP)

A layer 3 protocol designed for routing and facilitating communication across diverse networks through addressing and fragmentation.

IP Addressing

Functions to identify both the specific machine and the network it resides on to ensure proper packet delivery.

Fragmentation

The process where IP breaks down larger packets into smaller units to allow transmission across different network types.

Connectionless Nature

A characteristic of IP where datagrams are sent without established connections, meaning delivery order and arrival are not guaranteed.

IPv4 Address

A 4-byte address often represented in dotted decimal format (e.g., 128.243.28.210), allowing for roughly 4 billion addresses.

Class A Address

Designed for huge networks, containing up to 16.7 million addresses within the range of 1.x.x.x to 127.x.x.x.

Class B Address

Designed for medium-sized networks, accommodating 65,536 addresses within the range of 128.0.x.x to 191.255.x.x.

Class C Address

Designed for small networks, accommodating 256 addresses within the range of 192.0.0.x to 223.255.255.x.

CIDR (Classless Inter-Domain Routing)

A method using variable-length prefixes (e.g., /24) to replace fixed-size segments, improving address allocation efficiency and reducing routing table sizes.

Route Summarization

Also known as aggregation, this CIDR benefit allows a single routing table entry to represent a large block of networks, reducing router overhead.

IPv6

A protocol utilizing a 128-bit address space (3.4 \times 10^{38} addresses) developed to solve IPv4 address exhaustion.

Store-and-Forward Mechanism

A routing process where the entire packet must be received and error-checked before being sent to the next link, adding latency but ensuring data integrity.

Source Independence

A routing principle where routers only consider the destination address of a packet to determine the next hop, ignoring its origin.

Best-effort Delivery

A delivery model where the network does not guarantee that data will reach its destination or arrive in order, minimizing overhead and complexity.