Google Networking Best Practices for Large Deployments - Manual (Page 42)

42 Networking Best Practices for Large Deployments
Network Packet Captures
A network packet capture can help you to discover problems that may negatively affect the
round-trip time or overall latency for Google Apps users, such as:
• Different types of network flooding problems (ARP, TCP, UDP, IP, etc.)
• MTU mis-matches for Ethernet
• Malicious traffic on your network
Packet captures are helpful even though Google Apps typically uses HTTPS connections.
Packet captures will still show dropped packets, retransmits, window resizing, and evidence of
saturated links.
One way to gather this type of data is to enable port mirroring, which allows you to capture
traffic for a certain port or VLAN and divert it another port where a service listens and logs all
the traffic. Another approach is to use technologies such as
Wireshark to capture data on a
machine for later analysis.
Network multiping Helps monitor network latency, uptime, and
route changes.
Packet Capture Wireshark Performs packet captures.
RTT latency wbox Attempts to measure RTT of web application
latency using HTTP/TCP latency.
Trace tcptrace Similar to traceroute but uses TCP packets
rather than ICMP packets.
Type of Monitoring Tool Description