Tuesday, June 23, 2015

Tabula Rosa Systems Product Of The Day - ThousandEyes

One of Tabula Rosa's great new products is ThousandEyes which monitors LAN performance in real-time.

Please contact Tabula Rosa for more information.

ThousandEyes for Enterprise and IT Operations

Performance Challenges in Enterprise Environments
The performance of a corporate network is highly dependent on different factors. Applications like VDI and VoIP are specially sensitive to the real-time state of the network.

Infrastructure/Network Performance:

                Latency: Defined as the round-trip time (RTT) between the client and server, network latency depends mostly on the physical distance between the endpoints, as well as the congestion state of the network. Higher latencies cause higher application response times, as well as lower TCP (Transport Control Protocol) throughputs. TCP throughput is actually inversely proportional to the round trip time (WindowSize/RTT). Also, because of the slow start mechanism, TCP can be quite inefficient in taking advantage of available bandwidth. The impact of the RTT is exacerbated in the case of chatty protocols, that require N rounds to complete a transaction. A transaction that would take Nx5ms inside a LAN can take Nx100ms over the public Internet, making the application virtually unusable.
                                                                        Packet Loss: Packet loss can trigger TCP retransmissions and bring the throughput of the connection down. The throughput of a TCP connection is roughly proportional to sqrt(p) where p is the packet loss probability. So a connection with 2% loss has about 70% of throughput of a 1% loss connection. In fact it can be shown that in steady state, the window size of TCP with 1% loss is less than 10 packets. If each packet is 1,500 bytes long and the RTT is 100ms, that’s a throughput of 150 Kbytes/s.

                                                                        Capacity and Available Bandwidth: Capacity between two endpoints is the maximum data rate that can be achieved in the absence of any cross-traffic. Cross traffic will use a portion of the capacity, and the remaining is the available bandwidth, which determines how fast TCP connections can go. Available bandwidth in enterprise networks is typically limited by cost, not so much by technology. Currently a WAN MPLS access can cost anywhere from $300/Mbps/month to $1,000/Mbps/month (note: Access to broadband Internet is 30x less expensive in comparison). Most enterprises still route Internet traffic through their data centers (e.g. MPLS access) using Internet traffic backhauling because of security and control. This consumes expensive bandwidth in the corporate backbone.

                                                                        Routing Availability: Routing inside the enterprise is determined by interior routing protocols such as OSPF or IGRP. But for Internet traffic, different networks need to exchange routing information using the Border Gateway Protocol (BGP). BGP allows independent neighboring networks to talk to each other to decide what traffic they will exchange. This process is usually driven by economics rather than network efficiency, therefore routes are not always optimal from a latency/bandwidth point of view. BGP changes (e.g. misconfigurations) can render an entire network unreachable or induce severe performance degradation on applications (note: bgp convergence times are often in the order of 3-digit seconds.)

                                                                        Wireless Access (WLAN): Bad quality 802.11 wireless access in the branch office is a common cause for performance degradation of applications. This can be caused by degradation of the radio signal power (lower RSSI) that can be caused by interference or physical distance between the client and the access point. This is often a hard element to troubleshoot end-to-end since typically there is no access to this information without instrumenting the client or the access point.

As enterprises adopt Software-as-a-Service (SaaS), application performance becomes more dependent on what happens outside of the corporate network.
**Important note** - contact our company for very powerful solutions for IP management (IPv4 and IPv6, security, firewall and APT solutions:


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