Cisco IOS IP SLA Responder is a Cisco IOS Software component whose functionality is to respond to Cisco IOS IP SLA request packets. The IP SLA source sends control packets before the operation starts to establish a connection to the responder. Once the control packet is acknowledged, test packets are sent to the responder. The responder inserts a time-stamp when it receives a packet and factors out the destination processing time and adds time-stamps to the sent packets. This feature allows the calculation of unidirectional packet loss, latency, and jitter measurements with the kind of accuracy that is not possible with ping or other dedicated probe testing. Reference: UDP Jitter measures the delay, delay variation (jitter), corruption, misordering and packet loss by generating periodic UDP traffic. This operation always requires IP SLA responder. The command to enable UDP Jitter Operation is "ip sla responder udp-echo {destination-ip-address} [destination-port]

Certificate authorities (CAs) are responsible for managing certificate requests and issuing certificates to participating IPSec network devices. These services provide centralized security key and certificate management for the participating devices. Specific CA servers are referred to as "trustpoints." The command "crypto pki trustpoint name" declares the trustpoint and a given name and enters ca-trustpoint configuration mode. The command "enrollment terminal" specifies manual cut-and-paste certificate enrollment method. The certificate request will be displayed on the console terminal so that you may manually copied (or cut). The command "crypto pki enroll name" generates certificate request and displays the request for copying and pasting into the certificate server. The full configuration is shown in the reference below. Reference: https://www.cisco.com/c/en/us/td/docs/ios/ios_xe/sec_secure_connectivity/configuration/guide/convert/sec_pki_xe_3s_book/sec_cert_enroll_pki_xe.html