new FAQ: Why is my throughput intermittently slow on a dual NIC Linux system?

New FAQ entry for MIMIC SNMP Agent Simulator:


Q. Why is my throughput intermittently slow on a dual NIC Linux system?

A. If your Linux MIMIC system has multiple active network interfaces
connected to the same LAN, and you are experiencing drops in PDU throughput
while polling MIMIC agents in the SNMP simulation, it may be due to one network
interface running slower than the other. Linux will route traffic through
the NIC according to the arp tables regardless of the interface an agent
IP address is assigned to. The command "ethtool" run as root can be used
to discover the current speed and duplex settings of each NIC.

# ethtool eth0
Settings for eth0:
        Supported ports: [ TP ]
        Supported link modes:   10baseT/Half 10baseT/Full
                                100baseT/Half 100baseT/Full
        Supports auto-negotiation: Yes
        Advertised link modes:  10baseT/Half 10baseT/Full
                                100baseT/Half 100baseT/Full
        Advertised auto-negotiation: Yes
        Speed: 100Mb/s
        Duplex: Full
        Port: Twisted Pair
        PHYAD: 1
                Transceiver: internal
        Auto-negotiation: on
        Supports Wake-on: umbg
        Wake-on: g
        Current message level: 0x00000001 (1)
        Link detected: yes

Any protocol analyzer can be used to capture packets between the
walkhost and the agent to determine the MAC address of the NIC handling
the traffic.