in inglese ho trovato, sperando che sia di aiuto:
A call leg refers to the one-to-one signaling relationship between two user agents (UAs). The Call-ID is an identifier, carried in the SIP messages, that refers to the call. A call is a collection of call legs. A UAC starts by sending an INVITE; because of forking, it may receive multiple 200 OKs from different UAs. Each corresponds to a different call leg within the same call. Call is thus a grouping of call legs. In the call control spec, additional call legs are created through special mechanisms.
Call legs refer to end-to-end connections between user agents, rather than any relationship with proxies. Within a call leg, there are numerous transactions in both directions.

The request URI is not used in call leg identification.

The To and From field relate to local and remote in the following way. When Alice sends a request on a call leg to Bob, the From field contains the local address (Alice), and the To field the remote address (Bob). When a request is received by Bob, the To field is matched to Bob's local address, and the From field to the remote address (Alice).

The CSeq spaces in the two directions of a call leg are independent. Within a single direction, the sequence number is incremented for each transaction.

http://www.cs.columbia.edu/sip/faq/cache/23.html

Non ho trovato niente in italiano, ma non so se ho cercato bene.

Utilizzo "scalo" per non creare confusione con trasferimento della chiamata, anche automatico, appropriandomi del significato di "leg" in campo trasporti.

buon lavoro

paola l m

Discrete segment of a call connection. A call leg is a logical connection between the router and either a telephony endpoint over a bearer channel, or another endpoint using a session protocol.

Se ti può servire... Ciao

Seguone le definizioni di "call leg" date da vari glossari. Si tratta di un tratto di chiamata, ovvero del "dialogo" tra dispositivi di rete.

Interessante (vedi sotto) la definizione trovata in una mail:
"> Call leg: Another name for a dialog.
> Dialog: A dialog is a peer-to-peer SIP relationship between Various Authors"

Dalla mail risulta che la voce aggiornata di "call leg" [leg starebbe per 'tratto', 'segmento'] è "dialog".
Cercando la voce "dialogo", "dialoghi", si trovano link interessanti (riportati sotto).

A questo punto suggerisco di usare "dialogo (call leg)", che sembra, sulla scorta dei documenti riportati in conclusione, essere la voce italiana per "call leg".

Personalmente penso che "segmento di chiamata" potrebbe rendere l'idea, ma forse potrebbero esserci sovrapposizioni con altri significati.

Anche il Jackson sembra tradurre "dialog" con "dialogo" o "colloquio" (da intendersi con un computer ecc.).

http://www.hifn.com/support/Glossary_C.html

call leg
Discrete segment of a call connection. A call leg is a logical connection between the router and either a telephony endpoint over a bearer channel, or another endpoint using a session protocol.


http://www.cisco.com/univercd/cc/td/doc/product/access/acs_m...

Call leg
Segment of a call path. A logical connection between a telephone and a router, a router and a network, a router and a PBX, or a router and the PSTN using a session protocol. Each call leg corresponds to a dial peer.


http://www.pbxinfo.com/html/glossary.html

Call leg -A logical connection between the router and either a telephony endpoint over a bearer channel or another endpoint using a session protocol.

http://www.banknet.kz/~info/cisco/cc/td/doc/product/access/a...

Call leg
Segment of a call path. A logical connection between a telephone and a router, a router and a network, a router and a PBX, or a router and the PSTN using a session protocol. Each call leg corresponds to a dial peer.


http://lists.cs.columbia.edu/pipermail/sip-implementors/2001...

> Call leg: Another name for a dialog.
>
> Dialog: A dialog is a peer-to-peer SIP relationship between a Various
> Authors [Page 13] Internet Draft SIP October 26, 2001 UAC and UAS that
> persists for some time. A dialog is established by SIP messages, such as
> a 2xx response to an INVITE request. A dialog is identified by a call
> identifier, local address, and remote address. A dialog was formerly
> known as a call leg in RFC 2543.


http://www.dmi.unisa.it/people/sebillo/www/Reti.pdf
Dialoghi

http://www.astropa.unipa.it/CalcoloLan/BOLLETTINI/NI_3.pdf
Dialoghi

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Note added at 2002-06-04 20:56:33 (GMT)
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Gli ultimi due link riportati attestano l\'uso della voce \"dialoghi\"

deduco dai vari link e dalla stessa spiegazione che riporti tu nel testo.
SBC