Internet Speed Issue – How to use TCP window scaling option
From few simplifying test results on previous article "Internet Speed Issue – Why TCP window size is matter", indeed TCP window size made difference of…
How to setup FreeRADIUS server?
Tweet Here is a simple documentation how to setup FreeRADIUS server. It’s written by Korean. http://www.ibm.com/developerworks/kr/library/l-radius/
Preventing Security Attacks from all OSI 7 Layer
Tweet Let’s quickly look what kinds of Security Attacks on OSI 7 Layer. Layer 7. Application /6. Presentation/5. Session Layer – Virus, Warms, Tro-hourse, Buffer…
How to hide an access-list applied?
Tweet Sometime, you even don’t want to reply ICMP unreachable message response back to requester. It’s very simple. Here is how you do it. (Assume…
Basic QoS
Tweet There are 4 priority queues: high, medium, normal, low. The default queue is the normal queue, by default. The high and medium queues…
CAR(Committed Access Rate) ?
Tweet Committed Access Rate (CAR) is used to rate limit traffic. In this example, all ICMP traffic that exceeds the defined level will be dropped….
Random Early Detection (RED)?
Tweet Random Early Detection (RED) is a congestion avoidance mechanism that takes advantage of TCP’s congestion control mechanism. When it comes to Quality of Service,…
Issue on Cisco GigE port with FastEthernet port on 3Com switches
Tweet As you know, Cisco Systems is one of top vendor in Router and Switch market in the world since early 90’s. If someone asks who …
[Cisco] How to limit a rate on interface ?
Tweet The command ‘rate-limit’ is interface configuration command. It is used to setup a committed access rate (CAR) and distributed CAR (DCAR) policies. To remove…
Internet Speed Issue – How to troubleshoot(IPERF)
Most of the cases, FTP testing would be enough to isolate an issue if existed. However, sometime you need more deep testing and detailed output…
Internet Speed Issue – How to troubleshoot(FTP)
From previous article, Bandwidth VS. Throughput, now you can determine whether your throughput is on trouble or not. It means your Internet connection is slower…
Easy QoS 101 – What is QoS(Qaulity of Service)
Tweet QoS(Qaulity of Service), it is definetly one of hot topic in IT fields. Economically, most companes are suffering in thesedays. IT budget got cut…
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