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1500 questions
12
votes
7 answers

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 hops over the distance. The business requirement…
MattE
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12
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4 answers

Two hosts of different subnets connected to switch

Two host of different subnets, let it be A - 10.1.2.1/24 and B - 10.1.3.1/24 be connect to the same switch S. Can they communicate? So as far I understand: A sends a packets with IP of B S receives it and compare it with values in Stored…
ranger
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12
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7 answers

DHCP relay problem on interfaces secondary network

A secondary network was configured on an interface of a Cisco 2621 router and the ip helper-address commands put in place but no clients of that secondary network could pull DHCP addresses. We swapped the primary network and the secondary network…
Adam Loveless
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12
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8 answers

How do you convince management that 3560/3750s are a bad idea in your DC?

3560/3750s have small buffers and make good wiring closet switches. However I very often see these switches sitting in DCs. Lots of folks tend to use them as they are generally 1Gb and L3 capable. Is there a way to prove just how bad they are in DC…
mellowd
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12
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2 answers

why we can't create multiple loopback interfaces in Junos?

comparing to Cisco IOS , we can create any number of loopbacks on router , but on Junos you can create only one loopback interface (even logical units from same loopback) in the routing instance , did any one suggest or think about the reason for…
Mr.lock
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12
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6 answers

Best practice for dual-homing site with two ISPs?

I am subscribed to two ISPs, a fast expensive one and a cheap but slower one. They use different technologies, cable and ADSL, so there isn't much of a single point of failure, and all my comms equipment is powered from a UPS. ISPs in the UK go…
Morgaine
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11
votes
2 answers

IPv6 Subnetting - Block RA on Switches?

I'm currently planning a v6 only small datacenter network. Imagine for now one deployment consisting of 6 racks with 12 servers per rack. Each server has 2 NICs for two physically separate networks (management & data). The racks are…
paraa
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11
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2 answers

Trying to fit centralised firewall into network topology

I'm in the process of over-hauling our network, the issue I keep coming back to is: trying to bring layer 3 to the core, while still having a centralised firewall. The main issue I have here is that the "mini core" switches I've been looking at…
Geekman
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11
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2 answers

BGP Prefix Announcement Issue

I'm having a weird issue. Here is the setup. We have 2 Foundry SX's. SX01 ---> ISPA | | SX02 ---> ISPB I have a /24 from ISPA and another /24 from ISPB. Both /24's are able to be announced to each of the providers. iBGP runs between the two…
Network Samurai
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11
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3 answers

Is `0.0.0.0/1` a valid IP address? If so, what does it indicate?

I know that 0.0.0.0/0 represents a default route. But I would like to understand what does 0.0.0.0/1 represents? Is it even a valid thing in networking?
Deepak
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11
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5 answers

Why are rings not a favorite option in IT networks?

I'm an engineer in the automation field. I've been switching slowly to networking. I've started in the automation world 12 years ago. With an automation mindset, we use rings (like MRP rings) everywhere. However, I've noticed that IT network…
AhmedWas
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11
votes
3 answers

How does a router find the next hop when the receiver is in a distant IP network?

Say I want to send a frame to a web server, and let's say this web server is in a very distant IP outside my local network e.g. a Google server. I initially send the frame to my router. My router decapsulates the frame, reads the destination IP…
JohnDoeyyy
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11
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1 answer

How much RAM you actually need to keep whole global BGP routing table?

It seems that different sources claim very different RAM consumption for having whole BGP routing table information in RAM and having the router to correctly route the traffic. According to Calculating Cisco router memory requirements for full BGP…
Mikko Rantalainen
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11
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3 answers

Please help me understand this ADSL configuration

I've been working across many sites around the world with ADSL. The first output below is the one I've used many many times & I'm therefore most familiar with. It's from a site in the UK. interface ATM0 no ip address no atm ilmi-keepalive pvc…
Steve
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11
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2 answers

IPv6 DHCP Server vs Router

I am setting up a testing environment for dualstack. I currently have a server (Windows 2008 R2), 2 switches and a router installed and configured. The server is the Primary Domain Controller and it has the DHCP role installed. I am using VLANs to…
Joren
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