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1500 questions
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1 answer

Configuring a second MPLS connection for our backup Data center (BGP Closed User Group)

I'm a bit new to BGP and need a little assistance with a configuration change. We are currently using our MPLS connection for all traffic to all sites. Going forward We would want to segragate the Datacenter backup link from the other spoke sites…
mseanmiller
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4 answers

Cisco IOS cli prompts - any way to know which interface you are configuring?

I'm used to the Juniper and Extreme worlds more than Cisco. I'm able to get by OK, but some basic cli issues arise that have finally frustrated me enough. Inside a Cisco ASA 5505/5510 running 8.3+ or a Cisco 2901 router running 15.2. Is there a way…
TheCleaner
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DSCP trust boundary

I have performed some analysis and noticed that traffic coming in from the Internet contains a myriad of DSCP values. This traffic competes for voice and video resources on the internal network. How do I establish a trust boundary where all…
Dennis Olvany
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3 answers

How does Ethernet detect a collision in the CSMA/CD method?

I understand that Carrier Sense is essentially the NIC "listening" to the medium for any transmissions, Multiple Access means that multiple devices on the network can "listen" to the medium, and Collision Detection is the procedure it goes through…
user3662222
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3 answers

How do I configure a port as STP "non-edge" on Juniper EX switches?

Juniper EX switches automatically categorize a port as an spanning-tree "edge" (there should only be one device behind the port) or "non-edge" (another switch) port. You can force this mode for a port by configuring set protocols …
Sebastian Wiesinger
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7
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How does a network know whether to send via internet/wifi or through cellular service?

I have a decent understanding of networking, but this question popped up in my head randomly and I can't figure it out. For example, if I have an iPhone that is used on a 3G network but is also connected to my home wifi throughout the day, how does…
raisedandglazed
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2 answers

Why are ethernet / mac -addresses in hex and ip numbers in decimals?

Why are ethernet- / mac-addresses in hex (and have 48 bits) and ip numbers in decimals (and have 32 bits)? Does that have historical or practical reasons?
user44840
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When is an IPv4 TTL decremented and what is the drop condition?

When an IPv4 packet traverses a router or is processed by a host, the TTL is decremented and if the TTL is too low, the packet is dropped. My questions are: When is the TTL decremented? Before or after the packet is considered for dropping? What is…
joshlf
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6 answers

What is the benefit of a Cisco "top of rack" design?

Aside from the obvious cabling mess you avoid (which I know for us as network engineers is great, but hard to use as an excuse when reasoning with someone who sees no point in it), what do you gain versus copper straight through to a larger…
skrumcd
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7
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how to create managment access to SRX Lsys.

is there a way to configure separated admins, one for the SRX root lsys and another to a specific lsys? i'm trying to create two users that when you login with user1 you will login to the root lsys and when you login with user2 you will login to…
Zorik Meyman
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7
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2 answers

Switch security when in an unsecured location

I have a situation where I'm required to install a switch in a location that is physically insecure and has guests coming and going. It is in the audio rack of a sound desk at a facility that has lots of non-staff members that have physical access…
Mark Henderson
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1 answer

Troubleshooting "TCP Zero Window" Issues

I'm currently having a problem troubleshooting a trading application. Let me give a simple diagram of the current network setup (Gov't Stock Exchange Network Router)X-->(256kbs Leased Line)<--X(Telco Router)<-(100mbps fast E link)--->Our Network…
Rufi
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1 answer

How long is a frame really supposed to be, and when is a frame a babble?

I'm studying some networking things, and something I noticed in the interface counters on a Cisco switch (output of #sh int) one counter for 'babbles' 0 babbles, 0 late collision, 0 deferred Cisco defines babbles as 'Babble errors occur due to the…
awr
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7
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Won't GLBP confuse a switch's mac address-table?

Say for example two routers (R1 and R2) are connected to the same switch (SW1) and both routers have Gateway Load Balancing Protocol (GLBP) correctly configured as the First-Hop Redundancy Protocol (FHRP) solution. Router 1 has been elected the…
Joseph Shih
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6
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1 answer

Cisco 867 forward UDP port range

I need to forward an UDP port range to a specific private IP address in my LAN. In order to forward one port to an internal IP I do: access-list permit any any eq ip nat inside source static …
eldblz
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