Fastpath and Slowpath Packet Captures

The packet capture in MonSub takes place in Slowpath and Fastpath.

Slowpath

  • Slowpath PCAP captures the packets going through slowpath (application).​

    When option PFCP(49), GTPU(26), L3(19), and CSS(34) is enabled, N4 messages/data packets are shown from the time MonSub is enabled.

  • Uplink data packet is shown as incoming GTPU, rulematch, outgoing L3​.

  • Downlink data packet is shown as incoming L3, rulematch, outgoing L3.

Fastpath

  • Fastpath PCAP will capture the packets going through fastpath​.

  • For pure Fastpath packets, the uplink data packet is shown as incoming GTPU, outgoing L3.

  • Downlink data packet is shown as incoming L3, outgoing GTPU​.

  • Slowpath packets are also shown in Fastpath PCAP, while egressing the UPF in both directions.