Questions tagged [ethernet]
For questions relating to Ethernet networking, as defined by the IEEE 802.3 standards.
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What functionality does 802.3bd-2011 actually add to 802.3 Ethernet?
Looking for various documents and the IEEE standards, I can see that 802.3bd-2011 adds a MAC control frame for priority-based flow control. How does priority-based flow control differ from IEEE 802.1P/...
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What happens when 2 computers transmits at the same time to a 3rd one in a full duplex switch?
Consider the following scenario:
I have 2 PC's (PC1 and PC2) that wants to transmit at the same time to PC3 in a full duplex ethernet switch. Let's consider that all ports are in the same VLAN, so ...
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Do faster segments of a network mean faster flow rate or lower latency?
This is another one of those hypothetical questions. I've been trying to figure out whether or not having a faster 'segment' of a network in between host A and host B will translate into a faster flow ...
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Jumbo Ethernet Frame Deployment
What are some general guidelines for the successful deployment of jumbo frames in a routed environment?
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UDP Message Length Field and Pseudo Header
I'm learning some tcp/ip basics, and am having trouble understanding the Message Length field in UDP. In my book, it says that the Message Length represents the UDP header and data in octets, and ...
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Accurate strategy for measuring point-to-point link performance?
I have a requirement to provide an accurate means to demonstrate line performance over a flat layer2 1Gb point-to-point Ethernet circuit, approx 100 miles apart that seemingly goes through a number of ...
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Difference between LLDP and LLDP-MED
What is the difference between LLDP and LLDP-MED? Is LLDP-MED an add-on to LLDP or something completely different?
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Long Reach Ethernet
In our corporate headquarters we are looking at replacing a 20+ year old phone system and making the switch to VoIP. This is a high rise where we have some limits around options for cabling. ...
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Monitoring best practice for thresholding errors on an interface?
When monitoring interface errors, what percentage of traffic should you set your 'critical' threshold to according to best practices and does it depend on the interface type (T1, Ethernet etc)? It ...
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How do the different types of materials used in Ethernet cables affect reliability?
There are many metals used in different types of network cables, such as aluminum and copper. Some are expensive and some are cheap. What scenarios constitute the use of these types of different wire ...
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MAC address recycling?
Something I've always wondered about is MAC address exhaustion. Do hardware vendors keep track of MAC address allocation to their platforms, and then subsequently "reclaim" MAC addresses when a ...
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speed/duplex mismatch
How do mismatches occur; what is the impact of a mismatch on network connectivity; is resolution of mismatches really worth the effort; what are some ways to detect mismatches on a large scale?
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Introductory level explanation of VLANs
What's the basic use case(s) for VLANs?
What are the basic design principles?
I'm looking for something like a two paragraph executive summary style answer so I can determine if I need to learn ...
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Why does 1000BASE-T need Auto-MDIX?
A 100BASE-TX PC interface sends out its frames on pins 1,2 and receives frames on pins 3,6. If we connect this PC's NIC with that of another PC we cannot use a straightout cable, because the frames ...
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Are there any reasons to not use BFD?
In looking to implement Bidirectional Forwarding Detection (BFD) it seems to be very flexible in terms of timer tuning, light weight regarding any overhead and it's flexibility in terms of overall ...
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Are multiple links with different VLANs between two switches possible?
I'm not considering Etherchannel or LACP.
Given 2 Ethernet switches A and B, where both switches have port 0 configured as a tagged trunk for VLAN 100 and 101 and port 1 configured as a tagged trunk ...
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How can I diagnose a bridging (ethernet) loop?
Given that spanning tree has failed (or you don't have any spanning tree) and get an ethernet loop, what's the best way to diagnose where the problem is?
Which switch?, which cable? and so on.
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Emulate Ethernet frame loss for testing purposes [closed]
Maybe I am missing something rather basic, but I don't know so I figured I would ask.
In terms of testing, how sensitive various TDMoE are to BER and packet delay, I am looking into how to simulate ...
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TDMoE and QoS considerations
As mentioned in the previous question I am looking at sending voice communications over a Metro Ethernet connection shared also by data connections. In addition to the previous question I have this ...
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How sensitive is TDMoE to BER?
We are currently looking at connecting two Asterisk servers across a Metro Ethernet. This leads to a couple of questions I haven't been able to find answers to elsewhere.
The first involves bit ...
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How is the root bridge elected in STP?
How does STP/RSTP determine which bridge is the root bridge, and how are paths to the root bridge selected?
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When to choose fiber instead of twisted pair (copper)
These days both fibre and twisted pair are supporting 1000BASE-T and 10GBASE-T, but when do you choose one over the other? The obvious one is maximum cable length, but what are other factors which ...
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