# Session Description Protocol Session Description Protocol is a protocol, standard, or security technology recorded in [[Scanned_20260730-1706|Scanned_20260730-1706]]. In the reconstruction, SDP describes media types, transports, timing, and codecs; UAC and UAS are the client/server transaction roles of SIP user agents. ## Historical and Technical Context [[Session Initiation Protocol|SIP]] is an application-layer signaling protocol for creating, modifying, and terminating sessions; invitations carry session descriptions so endpoints can negotiate media ([RFC 3261](https://www.rfc-editor.org/info/rfc3261/)). Juniper identifies SIP as a predefined service using destination port 5060 and describes its role in distributing and modifying session descriptions ([Juniper SIP ALG](https://www.juniper.net/documentation/us/en/software/junos/alg/topics/topic-map/security-sip-alg.html)). [[Session Description Protocol|SDP]] describes media types, transports, timing, and codecs; UAC and UAS are the client/server transaction roles of SIP user agents. ## Role in Scanned_20260730-1706 The author is learning why SIP signaling and RTP media cannot be treated as a single fixed-port flow. The phrase “create pinholes, and cover it up” expresses the ALG's dynamic state behavior in informal language. ## Notebook Evidence - [[Scanned_20260730-1706|Scanned_20260730-1706]], PDF page 29: SIP and SDP. **Evidentiary status:** The page occurrence and transcription are notebook evidence. Technical identification follows the source reconstruction’s cited research. Co-occurrence does not by itself prove ownership, deployment, or a direct operational relationship. ## Relationships and Overlays On the cited page or pages, Session Description Protocol appears with [[Session Initiation Protocol|SIP]]. These are page-level or reconstruction-level relationships, not automatic claims of dependency. ## Cross-Notebook Significance This note supplies a concrete network-policy or evidence mechanism beneath the AIOps, security-operations, and governance concerns in [[Scanned_20260730-1802|Scanned_20260730-1802]]. It shows how dynamic state is created, observed, and retained at the protocol boundary. ## Missed Signals and Open Leads “cover it up” may mean close the pinhole after the session, mask internal addressing through NAT, or merely complete the explanation; do not over-interpret it as concealment. ## Sources - [[Scanned_20260730-1706|Scanned_20260730-1706]], especially PDF page(s) 29. - `Scanned_20260730-1706.pdf`, cited as a plain archival filename; the PDF is not linked from `wiki-notes`. - External research citations used for identification remain preserved in the source reconstruction. - [RFC 3261](https://www.rfc-editor.org/info/rfc3261/) - [Juniper SIP ALG](https://www.juniper.net/documentation/us/en/software/junos/alg/topics/topic-map/security-sip-alg.html)