RTCP SDES (`rtcp_sdes`)

Layer: Application and control
Header: variable length
Notes: MACsec / GTPv2-C / Diameter / SIP / RTP (P2)

Reached from

Lower layer	Selector	Value
`rtcp`	`packet_type`	202 (0xca) (re-decodes this layer)
`rtcp`	`packet_type`	0 (0x00) – 255 (0xff) (at least 4 octets remaining)
`rtcp_sr`	`version`	2 (at least 4 octets remaining)
`rtcp_rr`	`version`	2 (at least 4 octets remaining)
`rtcp_sdes`	`version`	2 (at least 4 octets remaining)
`rtcp_bye`	`version`	2 (at least 4 octets remaining)
`rtcp_app`	`version`	2 (at least 4 octets remaining)

Fields

Field	Type	Default	Auto	Description
`version`	`uint(2)`	`2`		RTCP version (2).
`padding`	`uint(1)`	`0`		P bit: padding octets at the end of the packet (Manual).
`source_count`	`uint(5)`		Number of items of `chunks`	Source count: SDES chunks or BYE identifiers (Auto).
`packet_type`	`enum(8)`	`202` (sdes)		Packet type (200 SR, 201 RR, 202 SDES, 203 BYE, 204 APP, 205 RTPFB, 206 PSFB, 207 XR).
`length`	`uint(16)`		Length of the header in 32-bit words (`-1`)	Packet length in 32-bit words minus one (Auto).
`chunks`	`list<struct>` — `source_count` items	1 items		SDES chunks: SSRC / CSRC and its items (type, length (Auto), text), ended by a null octet and padded to 32 bits.

`packet_type`

Value	Name
200 (0xc8)	`sr`
201 (0xc9)	`rr`
202 (0xca)	`sdes`
203 (0xcb)	`bye`
204 (0xcc)	`app`
205 (0xcd)	`rtpfb`
206 (0xce)	`psfb`
207 (0xcf)	`xr`

`chunks`

Each item is a group of the fields below.

Field	Type	Default	Auto	Description
`ssrc`	`uint(32)`	`305419896`
`items`	`list<struct>` — up to the terminator `00` (appended when building)
`padding`	`padding(4)`

`chunks` › `items`

Each item is a group of the fields below.

Field	Type	Default	Auto	Description
`type`	`enum(8)`	`1` (cname)
`length`	`uint(8)`		Size of `text` in octets
`text`	`bytes` — `length` octets

`chunks` › `items` › `type`

Value	Name
1 (0x01)	`cname`
2 (0x02)	`name`
3 (0x03)	`email`
4 (0x04)	`phone`
5 (0x05)	`loc`
6 (0x06)	`tool`
7 (0x07)	`note`
8 (0x08)	`priv`

Next layer

The next layer is selected by version; when the field is Auto the builder writes the value of the protocol stacked above.

Value	Protocol	Note
2	`rtcp`	at least 4 octets remaining
2	`rtcp_sr`	at least 4 octets remaining
2	`rtcp_rr`	at least 4 octets remaining
2	`rtcp_sdes`	at least 4 octets remaining
2	`rtcp_bye`	at least 4 octets remaining
2	`rtcp_app`	at least 4 octets remaining

Constraints

Level	Rule
warning	`version` = 2

Sample templates

rtcp-rr-bye — templates/protocols/voip/rtcp-rr-bye.wpg.yaml
rtcp-sr-sdes — templates/protocols/voip/rtcp-sr-sdes.wpg.yaml