6 ms·
It's P2P as far as the physical layer (L1) is concerned. Usually, full duplex requires two separate channels. The introduction of a hybrid on each end allows
by anonymousiam 10mo ago
It's P2P as far as the physical layer (L1) is concerned.
Usually, full duplex requires two separate channels. The introduction of a hybrid on each end allows the use of the same channel at the same time.
Some progress has been made in doing the same thing with radio links, but it's harder.
Nagle's algorithm is somewhat intertwined with the backoff timer in the sense that it prevents transmitting a packet until some condition is met. IIRC, setting the TCP_NODELAY flag will also disable the backoff timer, at least this is true in the case of TCP/IP over AX25.
- gerdesj 10mo agoSorry? Ethernet has had the concept of full duplex for several decades and I have no idea what you mean by: "hybrid on each end allows the use of the same channel at the same time." The physical electrical connections between a series of ethernet network ports (switch or end point - it doesn't matter) are mediated by CSMA. No idea why you are mentioning radios. That's another medium.
- Dylan16807 10mo ago> Ethernet has had the concept of full duplex for several decades and I have no idea what you mean by: "hybrid on each end allows the use of the same channel at the same time." Gigabit (and faster) is able to do full duplex without needing separate wires in each direction. That's the distinction they're making. > The physical electrical connections between a series of ethernet network ports (switch or end point - it doesn't matter) are mediated by CSMA. Not in a modern network, where there's no such thing as a wired collision. > Take a single switch with n ports on it, where n>2. How do you mediate ethernet traffic without CSMA - its how the actual electrical signals are mediated? Switches are not hubs. Switches have a separate receiver for each port, and each receiver is attached to one sender.
- switchbak 10mo agoMy understanding is that no one used hubs anymore, so your collision domain goes from a number of machines on a hub to a dedicated channel between the switch and the machine. There obviously won’t be collisions if you’re the only one talking and you’re able to do full duplex communications without issue.
- hylaride 10mo agoHubs still exist(ed), but nobody implemented half-duplex or CSMA from gigabit ethernet on up (I can't remember if it was technically part of the gig-e spec or not)
- deleted 10mo ago[deleted]
- nomel 10mo ago> My understanding is that no one used hubs anymore this is absolutely hilarious.
- switchbak 10mo agoYour comment is absolutely devoid of content. Admittedly, I’m no networking expert but it was my understanding that most installs now use switches almost exclusively. Are you suggesting otherwise? A quick search would seem to indicate I’m right. Do you mind elaborating on your snark?
- stephen_g 10mo agoA hybrid is a type of RF transformer - https://en.wikipedia.org/wiki/Hybrid_transformer https://en.wikipedia.org/wiki/Hybrid_transformer
- ahoka 10mo agoCSMA is last used with 10Mbit ethernet, so that’s why radios are only relevant.
- AnthonyMouse 10mo ago> It's P2P as far as the physical layer (L1) is concerned. Only in the sense that the L1 "peer" is the switch. As soon as the switch goes to forward the packet, if ports 2 and 3 are both sending to port 1 at 1Gbps and port 1 is a 1Gbps port, 2Gbps won't fit and something's got to give.
- mikepurvis 10mo agoRight but the switch has internal buffers and ability to queue those packets or apply backpressure. Resolving at that level is a very different matter from an electrical collision at L1.
- AnthonyMouse 10mo agoNot as far as TCP is concerned it isn't. You sent the network a packet and it had to throw it away because something else sent packets at the same time. It doesn't care whether the reason was an electrical collision or not. A buffer is just a funny looking wire.