Skip to main content
Commonmark migration
Source Link

I am writing an application that needs to ignore frames whose size is smaller than the minimum possible size of Ethernet/IGMP frames. I have researched extensively and found the following information:

  • The minimum size of an Ethernet frame is 64 bytes:

    The minimum size of an Ethernet frame is 64 bytes:

    Header + Payload + FCS (Frame Check Sequence) = 14 + 46 + 4 = 64 bytes

Header + Payload + FCS (Frame Check Sequence) = 14 + 46 + 4 = 64 bytes

  • If the payload of an Ethernet frame is smaller than 46 bytes, it is padded up to 46 bytes (so that collisions can be detected reliably).

    If the payload of an Ethernet frame is smaller than 46 bytes, it is padded up to 46 bytes (so that collisions can be detected reliably).

Now, looking at frames in my network using Wireshark, I noticed that most of them have a size of 60 bytes and that some IGMPv2 packets have a size of 46 bytes. These two findings surprised me because:

  1. I expected most frames to have a size of 64 bytes. (After investigating some more, I discovered that Wireshark does not include the 4-byte FCS in the displayed size, which explains why the most frames have a size of 60 bytes).

  2. I did not expect to see a frame with a size smaller than 64 bytes (or 60 bytes if we talk in terms of what Wireshark displays).

So my question relates to the second point, which remains unresolved: Is the format of an IGMP packet different from that of an Ethernet frame? If so, what is the minimum possible size of an IGMP packet?

I am writing an application that needs to ignore frames whose size is smaller than the minimum possible size of Ethernet/IGMP frames. I have researched extensively and found the following information:

  • The minimum size of an Ethernet frame is 64 bytes:

Header + Payload + FCS (Frame Check Sequence) = 14 + 46 + 4 = 64 bytes

  • If the payload of an Ethernet frame is smaller than 46 bytes, it is padded up to 46 bytes (so that collisions can be detected reliably).

Now, looking at frames in my network using Wireshark, I noticed that most of them have a size of 60 bytes and that some IGMPv2 packets have a size of 46 bytes. These two findings surprised me because:

  1. I expected most frames to have a size of 64 bytes. (After investigating some more, I discovered that Wireshark does not include the 4-byte FCS in the displayed size, which explains why the most frames have a size of 60 bytes).

  2. I did not expect to see a frame with a size smaller than 64 bytes (or 60 bytes if we talk in terms of what Wireshark displays).

So my question relates to the second point, which remains unresolved: Is the format of an IGMP packet different from that of an Ethernet frame? If so, what is the minimum possible size of an IGMP packet?

I am writing an application that needs to ignore frames whose size is smaller than the minimum possible size of Ethernet/IGMP frames. I have researched extensively and found the following information:

  • The minimum size of an Ethernet frame is 64 bytes:

    Header + Payload + FCS (Frame Check Sequence) = 14 + 46 + 4 = 64 bytes

  • If the payload of an Ethernet frame is smaller than 46 bytes, it is padded up to 46 bytes (so that collisions can be detected reliably).

Now, looking at frames in my network using Wireshark, I noticed that most of them have a size of 60 bytes and that some IGMPv2 packets have a size of 46 bytes. These two findings surprised me because:

  1. I expected most frames to have a size of 64 bytes. (After investigating some more, I discovered that Wireshark does not include the 4-byte FCS in the displayed size, which explains why the most frames have a size of 60 bytes).

  2. I did not expect to see a frame with a size smaller than 64 bytes (or 60 bytes if we talk in terms of what Wireshark displays).

So my question relates to the second point, which remains unresolved: Is the format of an IGMP packet different from that of an Ethernet frame? If so, what is the minimum possible size of an IGMP packet?

Bumped by Community user
added 1 character in body; edited tags
Source Link
Ron Maupin
  • 102.2k
  • 26
  • 125
  • 203

I am writing an application that needs to ignore frames whose size is smaller than the minimum possible size of Ethernet/IGMP frames. I have researched extensively and found the following information:

  • The minimum size of an Ethernet frame is 64 bytes:

Header + Payload + FCS (Frame Check Sequence) = 14 + 46 + 4 = 64 bytes

  • If the payload of an Ethernet frame is smaller than 46 bytes, it is padded up to 46 bytes (so that collisions can be detected reliably).

Now, looking at frames in my network using Wireshark, I noticed that most of them have a size of 60 bytes and that some IGMPv2 packets have a size of 46 bytes. These two findings surprised me because:

  1. I expected most frames to have a size of 64 bytes. (After investigating some more, I discovered that Wireshark does not include the 4-byte FCS in the displayed size, which explains why the most frames have a size of 60 bytes).

  2. I did not expect to see a frame with a size smaller than 64 bytes (or 60 bytes if we talk in terms of what Wireshark displays).

So my question relates to the second point, which remains unresolved: Is the format of an IGMP framepacket different from that of an Ethernet packetframe? If so, what is the minimum possible size of an IGMP framepacket?

I am writing an application that needs to ignore frames whose size is smaller than the minimum possible size of Ethernet/IGMP frames. I have researched extensively and found the following information:

  • The minimum size of an Ethernet frame is 64 bytes:

Header + Payload + FCS (Frame Check Sequence) = 14 + 46 + 4 = 64 bytes

  • If the payload of an Ethernet frame is smaller than 46 bytes, it is padded up to 46 bytes (so that collisions can be detected reliably).

Now, looking at frames in my network using Wireshark, I noticed that most of them have a size of 60 bytes and that some IGMPv2 packets have a size of 46 bytes. These two findings surprised me because:

  1. I expected most frames to have a size of 64 bytes. (After investigating some more, I discovered that Wireshark does not include the 4-byte FCS in the displayed size, which explains why the most frames have a size of 60 bytes).

  2. I did not expect to see a frame with a size smaller than 64 bytes (or 60 bytes if we talk in terms of what Wireshark displays).

So my question relates to the second point, which remains unresolved: Is the format of an IGMP frame different from that of an Ethernet packet? If so, what is the minimum possible size of an IGMP frame?

I am writing an application that needs to ignore frames whose size is smaller than the minimum possible size of Ethernet/IGMP frames. I have researched extensively and found the following information:

  • The minimum size of an Ethernet frame is 64 bytes:

Header + Payload + FCS (Frame Check Sequence) = 14 + 46 + 4 = 64 bytes

  • If the payload of an Ethernet frame is smaller than 46 bytes, it is padded up to 46 bytes (so that collisions can be detected reliably).

Now, looking at frames in my network using Wireshark, I noticed that most of them have a size of 60 bytes and that some IGMPv2 packets have a size of 46 bytes. These two findings surprised me because:

  1. I expected most frames to have a size of 64 bytes. (After investigating some more, I discovered that Wireshark does not include the 4-byte FCS in the displayed size, which explains why the most frames have a size of 60 bytes).

  2. I did not expect to see a frame with a size smaller than 64 bytes (or 60 bytes if we talk in terms of what Wireshark displays).

So my question relates to the second point, which remains unresolved: Is the format of an IGMP packet different from that of an Ethernet frame? If so, what is the minimum possible size of an IGMP packet?

deleted 12 characters in body; edited title
Source Link
Ron Maupin
  • 102.2k
  • 26
  • 125
  • 203

Minimum possible size of Ethernet/IGMP packetsframes

I am writing an application that needs to ignore packetsframes whose size is smaller than the minimum possible size of Ethernet/IGMP packetsframes. I have researched extensively and found the following information:

  • The minimum size of an Ethernet packetframe is 64 bytes:

Header + Payload + FCS (Frame Check Sequence) = 14 + 46 + 4 = 64 bytes

  • If the payload of an Ethernet packetframe is smaller than 46 bytes, it is padded up to 46 bytes (so that collisions can be detected reliably).

Now, looking at packetsframes in my network using Wireshark, I noticed that most of them have a size of 60 bytes and that some IGMPv2 packets have a size of 46 bytes. These two findings surprised surprised me because:

  1. I expected most packetsframes to have a size of 64 bytes. (After investigating some more, I discovered that Wireshark does not include the 4-byte FCS in the displayed size, which explains why the most packetsframes have a size of 60 bytes).

  2. I did not expect to see a packetframe with a size smaller than 64 bytes (or 60 bytes if we talk in terms of what Wireshark displays).

So my question relates to the second point, which remains unresolved: Is the format of an IGMP packetframe different from that of an Ethernet packet? If so, what is the minimum possible size of an IGMP packetframe?

Minimum possible size of Ethernet/IGMP packets

I am writing an application that needs to ignore packets whose size is smaller than the minimum possible size of Ethernet/IGMP packets. I have researched extensively and found the following information:

  • The minimum size of an Ethernet packet is 64 bytes:

Header + Payload + FCS (Frame Check Sequence) = 14 + 46 + 4 = 64 bytes

  • If the payload of an Ethernet packet is smaller than 46 bytes, it is padded up to 46 bytes (so that collisions can be detected reliably).

Now, looking at packets in my network using Wireshark, I noticed that most of them have a size of 60 bytes and that some IGMPv2 packets have a size of 46 bytes. These two findings surprised me because:

  1. I expected most packets to have a size of 64 bytes. (After investigating some more, I discovered that Wireshark does not include the 4-byte FCS in the displayed size, which explains why the most packets have a size of 60 bytes).

  2. I did not expect to see a packet with a size smaller than 64 bytes (or 60 bytes if we talk in terms of what Wireshark displays).

So my question relates to the second point, which remains unresolved: Is the format of an IGMP packet different from that of an Ethernet packet? If so, what is the minimum possible size of an IGMP packet?

Minimum possible size of Ethernet/IGMP frames

I am writing an application that needs to ignore frames whose size is smaller than the minimum possible size of Ethernet/IGMP frames. I have researched extensively and found the following information:

  • The minimum size of an Ethernet frame is 64 bytes:

Header + Payload + FCS (Frame Check Sequence) = 14 + 46 + 4 = 64 bytes

  • If the payload of an Ethernet frame is smaller than 46 bytes, it is padded up to 46 bytes (so that collisions can be detected reliably).

Now, looking at frames in my network using Wireshark, I noticed that most of them have a size of 60 bytes and that some IGMPv2 packets have a size of 46 bytes. These two findings surprised me because:

  1. I expected most frames to have a size of 64 bytes. (After investigating some more, I discovered that Wireshark does not include the 4-byte FCS in the displayed size, which explains why the most frames have a size of 60 bytes).

  2. I did not expect to see a frame with a size smaller than 64 bytes (or 60 bytes if we talk in terms of what Wireshark displays).

So my question relates to the second point, which remains unresolved: Is the format of an IGMP frame different from that of an Ethernet packet? If so, what is the minimum possible size of an IGMP frame?

Source Link
Loading