Ethernet speed connection 10/100 on PCB 19.5

[lyova]

Hello everybody.
For a long time I was not interested in the connection speed between my router and the device PCB 19.5.
Currently, the connection speed is 10Mb / full duplex and only connects automatically on router side.
All attempts to establish a manual connection to 100Mb / full duplex were unsuccessful.

The question is for those who know whether the device works with a connection speed of 100Mb / full duplex or is it possible a problem on the part of the device?

Thx.

[dupreezd]

Lyova, the network chip is a ENC28J60  and can only run 10Mb. For the amount of data sent, 100Mb is not really a requirement.

From the spec sheet
Ethernet Controller Features
• IEEE 802.3 compatible Ethernet controller
• Integrated MAC and 10BASE-T PHY
• Supports one 10BASE-T port with automatic polarity detection and correction
• Supports Full and Half-Duplex modes
• Programmable automatic retransmit on collision

Hope this help.

Dries

[mwaters]

I forgot about that, Dries. In some cases, a single 10mbps device can slow down part or all of a 100/1000 LAN.

All is well with a mix of 100/1000 devices (full 50mbps broadband speed achieved), but when a 10base-T device is attached (directly to router or through a gigabit switch), internet traffic is unable to get beyond 10mbps on ANY device on the entire network!!

The link speeds are still individually negotiated to 100 or 1000 (or so they claim), but something is dragging traffic down to 10Mbps. As soon as the 10base-t device is disconnected or powered off, everything returns to normal.

[dupreezd]

Mike, I might be wrong, but reading the quote, it looks like someone was having a problem and asking for help.

In the *old* days this was true in the case of HUBS. There data was received on one port and sent out to all the other ports causing slowdowns.

Todays new modern switches works totally different. Since switches operates at the Data Link Layer (layer 2), data received on one port is only sent out to one port by means of MAC address learning inside the switch resulting in wire speed operation.

"All switches contain some high-speed buffer memory in which a frame is stored, however briefly, before being forwarded onto another port or ports of the switch. This mechanism is known as store-and-forward switching. All IEEE 802.1D-compliant switches operate in store-and-forward mode, in which the packet is fully received on a port and placed into high-speed port buffer memory (stored) before being forwarded. A larger amount of buffer memory allows a bridge to handle longer streams of back-to-back frames, giving the switch improved performance in the presence of bursts of traffic on the LAN. A common switch design includes a pool of high-speed buffer memory that can be dynamically allocated to individual switch ports as needed."

My ISP router have 4 x 1Gb ports, but I don't plug any 'slow' devices into those ports. Rather, I have a 8 port managed Layer 2 Cisco switch (2960G) with a 1Gb uplink connected to the router. I use the switch to control traffic flow from the 'slow' devices. I regularly monitor the switch performance and have not seen any packet drops, buffer overload or latency issues.

On the other hand, these ISP routers are not commercial grade and could possibly cause network issues and packet drops. The reason why they are not used in Data Centers but rather $$$$ routers.

Also there is a difference in performance between a $10 and $100 switch.

Dries

[mwaters]

Thank you, Dries! I see that you're pretty knowledgeable about this. I just learned something.

I have a homemade pfSense router, which feeds a D-link 16-port switch, and a wireless router and all other devices are connected to that. Sounds like if I test the speed, I'll find that the 10mbps port on the lightning receiver isn't slowing the rest of my LAN down.

I don't know what a managed switch is.

[kevinmcc]

Thank you, Dries! I see that you're pretty knowledgeable about this. I just learned something.

I have a homemade pfSense router, which feeds a D-link 16-port switch, and a wireless router and all other devices are connected to that. Sounds like if I test the speed, I'll find that the 10mbps port on the lightning receiver isn't slowing the rest of my LAN down.

I don't know what a managed switch is.

Managed switch you can log in to the switch can change parameters.

Configure the ports to be for VLANs, Trunks vs Access, manually set speed and duplex, etc...

Normally used in the business world.

[mwaters]

Thanks Kevin. That's kind of what I figured. I never needed those features.