503
SIP
503 Service Unavailable
The server is temporarily unable to process the request due to overloading or maintenance. The client should retry after the time indicated in the Retry-After header.
Quand vous voyez ce code
During server overload, maintenance windows, or when the server is rate-limiting requests. Common during traffic spikes.
Comment résoudre
Wait for the time specified in the Retry-After header. If persistent, check server capacity and consider load balancing across multiple SIP proxies.
Spécification
Codes associés
Équivalents inter-protocoles
Comparer avec
Guides
401 Unauthorized vs 403 Forbidden: When to Use Each
Security & Authentication
SIP Response Codes: Understanding VoIP Call Flow
Real-Time Protocols
SIP Call Flow: Understanding Session Setup
Real-Time Protocols
WebRTC Signaling with SIP and WebSocket
Real-Time Protocols
RFC 3261: SIP Protocol Deep Dive
Protocol Deep Dives
TLS 1.3: Faster, Simpler, More Secure
Protocol Deep Dives
Spécifications
Glossaire
Status Code
Request Method (HTTP Verb)
TLS Handshake
Authentication
TCP/IP
Port Number
NAT (Network Address Translation)
Socket
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RFC (Request for Comments)
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STUN (Session Traversal Utilities for NAT)
TURN (Traversal Using Relays around NAT)
SDP (Session Description Protocol)
SIP INVITE
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SIP Redirect Server
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SIP User Agent
SIP Trunk
RTP (Real-time Transport Protocol)
SRTP (Secure Real-time Transport Protocol)
SIP ACK
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SIP OPTIONS
SIP SUBSCRIBE/NOTIFY
B2BUA (Back-to-Back User Agent)
SBC (Session Border Controller)
Codec Negotiation
SIP Response Classes
VoIP (Voice over IP)
Presence (SIP)
PBX (Private Branch Exchange)
MFA (Multi-Factor Authentication)
TLS Versions