3/13/2024 0 Comments Ping loopback packet infoNexus_7000# ethanalyzer local interface inband capture-filter "host 10.48.1.50 and icmp" limit-captured-frames 100 | no-more Success rate is 99 percent (994/1000), round-trip min/avg/max = 1/1/4 msĪ quick Ethanalyrzer on the N7K shows these ICMP requests/replies at the CPU level of the N7K, therefore making it prone to rate-limiting by CoPP. Sending 1000, 100-byte ICMP Echos to 10.48.1.50, timeout is 2 seconds: The ip address 10.48.1.50 is an ip address of an SVI configured on a Nexus 7000 : Here is an example of the type of packet loss one can expect when trying to ping a Nexus 7000. One rate, two color, and two rate, three color policing are supported. Glean packets are policed with default-class. If no policer is attached to a class, then a default policer is added whose conform action is drop. Conform, exceed, and violate actions (transmit, drop, mark-down) can be set. After a packet is classified, the packet can also be marked and used to assign different priorities based on the type of packets. In order to protect the Supervisor, the CoPP separates data plane packets from the control plane packets. However, CoPP is a security feature and not part of QoS. The CoPP feature is modeled like an input QoS policy attached to the special interface called the control-plane. It controls the rate at which packets are allowed to reach the Supervisor. It has no impact on hardware switched traffic through the box.ĬoPP is a hardware-based feature that protects the Supervisor from DoS attacks. NOTE - CoPP only applies to traffic destined to the switch itself (control plane). This is the main motivation behind CoPP on this platform. Loss of these control plane packets can create network instability, so it is very important to protect the CPU from traffic that could potentially cause high utilization. The CPU however, is not designed for extensive packet forwarding and is typically reserved for the processing and creation of control plane packets such as routing protocol hellos, BPDUs, LACP, CDP, etc. The main asset of the Nexus 7000 (as well as other Cisco switches) is the ability to switch packets in hardware using high speed ASICs. However, when pinging a Nexus 7000, it is very common to see packet loss due to the default behavior in which the Nexus 7000 uses Control Plane Policing (CoPP) to rate-limit certain types of traffic to the CPU. As ping is a common tool used to test connectivity in networks, it is not uncommon for users to try to ping a Nexus 7000 as a test. Cisco Nexus 7000 Series Switches offer one of the most comprehensive data center network feature sets in a single platform.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |