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How does a WiFi range extender work?

I have a WiFi base station, and a WiFi range extender. Both of them have the same SSID. When a device connects to that SSID, what exactly happens? How does the device know that base station and range extender are part of the same network and no…
Johannes Ernst
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Should portfast be used on a port potentially connecting to an unmanaged switch?

I understand the basics of how spanning tree works and why you would want to use portfast on user access ports. When dealing with a topology with a large number of dumb switches under desks and other undocumented locations do you really want to…
Tim Brigham
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Why use IP if we already have a MAC address?

I am preparing for ICND1 exams and recently started to learn about different Cisco devices. I have just come to know how the packet is generated to be transmitted over a network, or outside the network. For example, When the packet is generated, it…
Sufiyan Ghori
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Routing traffic out different links from the same BGP AS

I have two sites, A and B, in BGP AS 65000, and a third site, C, in AS 65001. All three sites have connectivity via carrier MPLS and there is internal connectivity between sites A and B. I am trying to influence BGP so that traffic from site A to…
Jeremy Stretch
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Why does an Ethernet cable have four pairs?

I'm curious about why 10Base-T and then 100Base-T Ethernet networks used cables which had four pairs if they only needed two? Were there some cables that only had two pairs? If we wanted to increase the speed of Ethernet further in the future, could…
UnderAnOpenSky
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IPv6: Why not use /126 on P2P links for IPv6?

In IPv4 we use /30 to conserve addresses. So why do some people recommend using /64 on P2P links instead of /126? I get using a /64 on regular subnets but isn't using a /64 when there will only ever be two addresses in use on P2P links tremendous…
bahamat
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Network latencies between opposite ends of the Earth

This is just out of curiosity. when I pinged domains such as bbc.co.uk and google.com (in California), I get latencies of around 5ms as below: 64 bytes from xx: icmp_seq=0 ttl=55 time=2.940 ms 64 bytes from xx: icmp_seq=1 ttl=55 time=3.785 ms 64…
user58476
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2 answers

Is it common for ISPs to connect to each other directly?

I'm reading up on the relationship between latency and ISP interconnectivity (that higher ISP interconnectivity results in lower latency, which makes sense to me). My understanding is that IXPs provide the primary means of ISPs to connect with each…
Zach Smith
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How is 8 bits sufficient for the TTL in an IP header?

The TTL (Time to Live) is an 8-bit field in the IPv4 header. It can take any value from 0 to 255. If this means that the packet can take a maximum of 255 hops (routers) on its way to its destination, then the packet will be discarded. How is it…
reddi hari
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What does TCP DUP ACK mean?

In Wireshark, I see TCP duplicate ACK packets sent from the receiver to the sender. What does it mean? Does it imply packet loss? Thank you
John T
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How do you get an ASA to announce NAT'd 'outside' addresses in to an OSPF zone?

Device arrangement is as follows: BGP Peers + | | +------+-------+ | | | Juniper MX5 | | | +------+-------+ |.254 OSPF | 10.0.1.0/24 |.1 +------+-------+ | | | Cisco…
SimonJGreen
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6 answers

IPv4 Segment 100.64.0.0/10

I recently got to know that IP segment 100.64.0.0/10 has been reserved by IANA for 'Shared Address Space'. My question is: Can I use the IP Segment 100.64.0.0/10 as a private range in my network (like the way we are using 10.0.0.0/8)? If yes, then…
Gaurav Kansal
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Can DHCP Server determine client's OS?

Is it possible for the DHCP Server to determine the client operating system? I'm working on a monitoring tool for gateways on local networks that is web-based and would like to be able to somehow determine what OS a device on the network is running…
Michael Lang
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Ethernet autonegotiation differences between (10M | 100M | 1G) Ethernet

I am studying for CCNA and on Wendell Odom's book is said that(regarding autonegotiation): When autonegotiation fails on one node, to choose (half/full-duplex) we must use the rule: If you have a 10/100 Mb/s interface -> use half-duplex If you have…
BrunoMCBraga
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Finding transparent firewall packet loss

We use the Cisco ASA 5585 in a layer2 transparent mode. The configuration is just two 10GE links between our business partner dmz and our inside network. A simple map looks like this. 10.4.2.9/30 …
user2096
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