What is the difference between Packet and Frame?

Introduction

In computer networks, data is sent between devices using protocols and layers. Each layer has its way of packaging and handling data. There are two types of data units: packets and frames. Packets are used in the network layer, while frames are used in the data link layer. But what is the fundamental difference between packet and frame? In this blog, we will discuss the difference between the two and define the frame and the packet in detail.

Before getting into more details, let’s first understand the difference between Packet and Frame.

Frame vs Packet

Below, we have explained the difference between packet and frame in a tabular form based on different factors.

Now, that we have a basic understanding of the difference between packet and frame. Below we have explained what a frame and packet really are.

What is Frame in Computer Network?

Frames are the building blocks of the OSI model data link layer. This layer facilitates data transfer between neighboring nodes within a network, such as two computers connected by a cable or wireless link. The data link layer also encompasses functions like error detection, correction flow control, and medium access control.

A frame comprises three components: a header, a payload, and a trailer. The header carries details like the source and destination MAC addresses. The sender and the source MAC addresses represent the addresses of devices on the network. Meanwhile, the payload contains the transmitted data, like an IP packet or an ARP request. The trailer includes a checksum or cyclic redundancy check (CRC) that helps identify any errors in the frame.

The format and size of a frame depend on the type of data link protocol that is used, such as Ethernet, Wi-Fi, Bluetooth, etc. For example, an Ethernet frame can have a maximum size of 1518 bytes, while a Wi-Fi frame can have a maximum size of 2346 bytes.

Below, you can see the frame format.

What is a Packet in Computer Networks?

Another data unit is commonly known as a packet within the network layer of the OSI model. The network layer allows the transmission of data across different networks like the Internet. The network layer carried out responsibilities such as routing, logical addressing, fragmentation and reassembly congestion control, and quality of service.

A packet comprises two components: a header and a payload. The header stores details such as source and destination IP addresses representing the addresses of devices on the network. On the other hand, the payload contains the data being transmitted, like a TCP segment or an ICMP message.

The format and size of packets vary depending on the network protocol employed, such as IPv4 or IPv6. For instance, an IPv4 packet can have a size of 65535 bytes, while an IPv6 packet can reach up to 65575 bytes in size.

Below, we have shown the packet format for better understanding.

Below, we have explained the frame vs packet in detail and some examples.

Difference Between Packet and Frame

One of the main difference between Packets and Frame is that a packet is a unit of data at the network layer that contains network addresses and payload, while a frame is a unit of data at the data link layer that includes physical addresses and error-checking bits. Some of the other difference between packet and frame are:

1. OSI Layer: When we talk about the frame, it is a data link layer, i.e., layer 2 entity, whereas the packet is a network layer, i.e., layer 3 entity. This simply means that a frame can only be transmitted within a LAN. On the other hand, a packet can be routed across different networks.
2. Addressing: In the case of a frame, it uses a physical address (MAC address), whereas a packet utilizes a logical address (IP address). This means that a frame can only identify the source and destination NICs within a LAN, whereas a packet can easily identify the source and destination across different networks.
3. Correlation: When discussing the correlation between the packet and a frame, a packet can be encapsulated within one or more frames. It totally depends on the size of the packet as well as the MTU (Maximum Transmission Unit) of the underlying network. Generally, a frame can carry a single packet or more than one packet, depending on the protocols used by the data link layer. For example, Ethernet frames can carry only one IP packet, whereas HDLC frames can carry multiple IP packets.
4. Functioning: When we talk about the packet, it encapsulates the data from higher layers and provides logical addressing and routing information for end-to-end delivery. On the other hand, the function of a frame is to encapsulate the packet from the network layer in order to provide physical addressing and error detection information for hop-by-hop delivery.

These are the difference between Packet and Frame.

Frequently Asked Questions

Q1. What is the difference between frames vs packets vs bits?

Frames are data units with headers and trailers. Packets are data units with headers only. Bits are binary digits that transmit data.

Q2. What is called Packet?

A packet is a unit of data that travels across a network. It contains information such as the source, destination, and content of the message.

Q3. Is a packet larger than a frame?

A packet is a data unit that usually travels across different networks. Frame is the one who carries the packet on a physical link. Therefore, a packet can be larger than a frame.

Q4. What is the difference between frame loss and packet loss?

Frame loss happens when a frame is either dropped or discarded by a network device due to many reasons, such as congestion. Meanwhile, packet loss happens when a packet is dropped by the network or, for some reason, gets corrupted during transmission. Both these not only affect the performance but also the quality.

Conclusion

In this blog, we have discussed frame vs packet in detail. Now, we have a basic understanding that the packets are utilized within the network layer while frames operate within the data link layer. Apart from that, we have discussed that the frame contains physical addresses, whereas packets contain logical addresses. In addition to this, we also have shown the frame and packet format.

Understanding the difference between packet and frame is crucial as it provides insight into the transmission of data across layers and protocols within computer networks. Additionally, this knowledge helps in the identification and resolution of network issues while optimizing network efficiency. Choose CCNA Course to learn the two topics in depth.