Posted On: Dec 9, 2024
Amazon Transit Gateway (TGW) now supports per availability zone (AZ) metrics delivered to CloudWatch. Furthermore, TGW now supports Path Maximum Transmission Unit Discovery (PMTUD) for effective mitigation against MTU mismatch issues in their Amazon Web Services China networks.
TGW allows customers to monitor their global network through performance and traffic metrics such as bytes in/out, packets in/out, and packets dropped. Until now, these metrics were available at an attachment level, and aggregate TGW levels. With this launch, customers have more granular visibility into AZ-level metrics for VPC attachments. AZ-level metrics enable customers to rapidly troubleshoot any AZ impairments and provide deeper visibility in AZ-level traffic patterns across TGW.
TGW now also support standard PMTUD mechanism for traffic ingressing on VPC attachments. Until now, jumbo sized packets exceeding the TGW MTU (8500 bytes) would get silently dropped on VPC attachments. With this launch, an Internet Control Message Protocol (ICMP) Fragmentation Needed response message is sent back to sender hosts allowing them to remediate packet MTU size and thus minimize packet loss due to MTU mismatches in their network. PMTUD support is available for both IPv4 and IPv6 packets.
The per-AZ CloudWatch metrics and PMTUD support on TGW are available in both Amazon Web Services China (Beijing) Region, operated by Sinnet and the Amazon Web Services China (Ningxia) Region, operated by NWCD. For more information, see the Amazon Transit Gateway documentation pages.