| Target release | 1.0 |
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| Epic | |
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| Document status | |
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| Document owner | |
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| Designer | |
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| Developers | |
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| QA | |
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Goals
- The current BLF and Extension mapping implementations for D8xx IP phone series are similar, but with a few differences and partly erroneous behaviour. Therefore, it is desired to align both implementations by using XML definitions instead. Furthermore, the requirements should be re-defined to communicate a clear result.
- Avoid confusion for customers
- Improve user experience
- Improve performance
Background and strategic fit
BLF is a valuable feature for Snom customers, like enterprises who are looking to assist in connecting their customers to a live, available person as well as save business phone use time. Overall, it enables businesses to streamline their communication and better serve customers. BLF aka Extension monitoring has been utilized in numerous ways by businesses using Snom phone systems with multiple extensions.
Use cases
- Use case#1: A secretary's phone shall display the call status of the boss's line, allowing the secretary to know whether the boss is on a phone call or not. This will enable the secretary to make the decision to put the new caller on hold or let them through to the boss.
- Use case#2: Call centers and customer support groups have also a need for BLF: it enables employees to see if their colleagues are free to take a support call or if their supervisor is on another line and unable to help another customer.
- Use case#3: BLF is needed by teams working on a specific project: supervisors can monitor team members' extensions and vice versa so all team members are aware of each other's current status.
Preconditions
On Snom IP phones acting as UAS, any SIP extension having an active subscription of its state changes, shall sent a notification SIP message (NOTIFY) to the UAC, when one of the following state changes occur:
- from any state => terminated
- from any state => trying
- from any state => early/proceeding
- from any state => confirmed
The NOTIFY XML body must contain the necessary information for the UAC to perform state translation and visualization.
Requirements
| # | Requirement title | Functionality | Importance | Implementation status |
|---|
| 1 | D8XX:PFK-mapping:BLF-XML:General-Functionality | On D8xx IP phones, any PFK (programmable function key - physical or virtual) can be assigned to a key type called "BLF-XML", and a key number, which corresponds to a SIP extension on another IP phone in the same VoIP environment. The following specific functionality is required: - Monitoring states of the configured SIP extension
- Quick-dial to the configured SIP extension in idle state
- Pick-up an incoming call to the configured SIP extension
| | |
| 2 | D8XX:PFK-mapping:BLF-XML:Configuration | The assignment shall be configured either manually via web user interface (WUI) and/or phone user interface (PUI), and automatically via auto-provisioning (HTTP/TFTP setting server), SRAPS, or remote management (TR-069). | | |
| 3 | D8XX:PFK-mapping:BLF-XML:Subscription | The assignment shall initiate the SIP subscription process according to RFC 3265. | | |
| 4 | D8XX:PFK-mapping:BLF-XML:Monitoring:Translation | Dialog states of the configured SIP extension shall be monitored, processed, and translated according to its direction. | UAS state | Dialog state (NOTIFY) | Direction | Translated state |
|---|
| idle mode | terminated/none of the below mentioned | - | idle |
|---|
offhook | trying | initiator | offhook |
|---|
| incoming call ringing | early/proceeding | recipient | ringing |
|---|
incoming call accepted | confirmed | recipient | talking |
|---|
outgoing call ringing | early/proceeding | initiator | calling |
|---|
outgoing call accepted | confirmed | initiator | talking |
|---|
| | |
| 5 | D8XX:PFK-mapping:BLF-XML:Actions | When the PFK is pressed, the following actions are allowed according to the translated state | Translated state | idle | offhook | calling | ringing | talking |
|---|
| Allowed actions | Quick-dial | ? | ? | Pick-up | ? |
|---|
| | |
| 6 | D8XX:PFK-mapping:BLF-XML:Monitoring:Visualization | On D8xx series, during an active subscription, state changes of the monitored SIP extension shall be visualized on both, PFK LED and PFK label. | | |
| 7 | D8XX:PFK-mapping:BLF-XML:Monitoring:Visualization:LED | The PFK LED behaviour and colour shall be according to the translated state: | Translated state | idle | offhook | calling | ringing | talking |
|---|
| LED behaviour | off | on | on | blinking | on |
|---|
| LED colour | - | red | red | red | red |
|---|
| | |
| 8 | D8XX:PFK-mapping:BLF-XML:Monitoring:Visualization:Label:Areas | The PFK label shall be composed of 3 areas: | (A) icon area | (B) name area | | (C) state area |
| | |
| 9 | D8XX:PFK-mapping:BLF-XML:Monitoring:Visualization:Label:icon-area | The label icon area (A) shall contain an icon and colour according to the translated state | Translated state | idle | offhook | calling | ringing | talking |
|---|
| Icon (suggestion from fkey_icons) | | | | | |
|---|
| Name | kIconTypeFkeyBlfIdle | kIconTypeFkeyBlfOffhook | kIconTypeFkeyBlfCalling | kIconTypeFkeyBlfRinging | kIconTypeFkeyBlfTalking |
|---|
| Colour | grey/white | red | red | yellow | red |
|---|
| | |
| 10 | D8XX:PFK-mapping:BLF-XML:Monitoring:Visualization:Label:name-area | The label name area (B) shall contain a text derived from display name or number (configurable) according to translated state and direction. Depending on the available space, the text shall be scrolled. | Translated state | idle | offhook | calling | ringing | talking |
|---|
| Direction | - | initiator | initiator | recipient | initiator | recipient |
|---|
| Text (based on target) | local | local > | local > remote | remote > local | remote <> local | local <> remote |
|---|
| Text colour | white | white | white | white | white | white |
|---|
| Example (using number) | 101 | 101 >
| 101 > 102 | 102 > 101 | 102 <> 101
| 101 <> 102
|
|---|
| Example (using display name) | Alex | Alex > | Alex > Alice | Alice > Alex | Alice <> Alex | Alex <> Alice |
|---|
| | |
| 11 | D8XX:PFK-mapping:BLF-XML:Monitoring:Visualization:Label:state-area | The label state area (C) shall contain a text and colour representing the translated state | Translated state | idle | offhook | calling | ringing | talking |
|---|
| text | idle | offhook | calling | ringing | talking |
|---|
| colour | white | white | white | white | white |
|---|
| | |
Software Requirement Specification (SRS)
Based on user interactions, the UAS sends SIP NOTIFY messages to the UAC. By means of XML definitions, the information in the SIP NOTIFY XML body are translated into variables, that are known to the UAC phone application and can be processed to show the desired results.
| Interactions | SIP NOTIFY XML body | XML definition | Display |
|---|
| UAS | UAS => UAC | UAC translation rules | Complete rule set | PFK LED & label (number) | PFK LED & label (display name) |
|---|
| goes offhook | dialog state => trying NOTIFY
...
<?xml version="1.0"?>
<dialog-info
xmlns="urn:ietf:params:xml:ns:dialog-info"
version="..."
state="full"
entity="sip:101@...">
<dialog id="..." >
<state>trying</state>
</dialog>
</dialog-info> |
| translate state => offhook - quick dial not allowed
- pick-up not allowed
...
<NotifyParsingRules type="state">
...
<level3
translates_to="offhook">/dialog-info/dialog/state[.="trying"]
</level3>
...
</NotifyParsingRules>
...
<action>
<invite target="$(subscr_uri)"
when="on press"
states="idle"/>
<invite target="$(remote_uri)"
when="on press"
state="ringing"
request_uri="$(remote_uri)"
replaces="$(call_id);to-tag=$(remote_tag);from-tag=$(local_tag)"/>
</action> |
|
<ReplacementPlan>
<!-- This defines the name of the entry in the Function Keys page under Type -->
<key id="BLF-new">
<general type="BLFSampleDefinition" />
<initialization>
<!-- only add the UAS IP here, extension number is replaced from WUI as variable $(ui_argument) -->
<variable name="subscr_proxy" value="10.110.22.35"/>
<!-- initial value for the state variable: off means, that after bootup this button has state off -->
<state value="off"/>
</initialization>
<!-- a subscription of event-type dialog will be initiated to the URI defined -->
<subscription type="dialog" to="<sip:$(ui_argument)@$(subscr_proxy)>" for="$(ui_argument)@$(subscr_proxy)"/>
<!-- checks if a SIP NOTIFY message belongs to this particular button
level is ok, if the condition inside the tags is matched -->
<NotifyParsingRules type="applies">
<level1 translates_to='OK'>/dialog-info[@entity="sip:$(ui_argument)@$(subscr_proxy)"]</level1>
</NotifyParsingRules>
<!-- translates the button state based on the body of the SIP NOTIFY -->
<NotifyParsingRules type="state">
<level1 translates_to="ringing">/dialog-info/dialog/state[.="early"]</level1>
<level1-1 translates_to="calling">/dialog-info/dialog[@direction="initiator"]</level1-1>
<level2 translates_to="ringing">/dialog-info/dialog/state[.="proceeding"]</level2>
<level2-1 translates_to="calling">/dialog-info/dialog[@direction="initiator"]</level2-1>
<level3 translates_to="offhook">/dialog-info/dialog/state[.="trying"]</level3>
<level4 translates_to="talking">/dialog-info/dialog/state[.="confirmed"]</level4>
<level5 translates_to="idle"/>
</NotifyParsingRules>
<!-- Call pickup: fetch variable call_id from call-id of NOTIFY body -->
<NotifyParsingRules type="variable" id="call_id" state="ringing">
<level1 fetch_attribute="call-id">/dialog-info/dialog[@call-id]</level1>
</NotifyParsingRules>
<!-- Call pickup: fetch variable remote_tag from remote-tag of NOTIFY body -->
<NotifyParsingRules type="variable" id="remote_tag" state="ringing">
<level1 fetch_attribute="remote-tag">/dialog-info/dialog[@remote-tag]</level1>
</NotifyParsingRules>
<!-- Call pickup: fetch variable local_tag from local-tag of NOTIFY body -->
<NotifyParsingRules type="variable" id="local_tag" state="ringing">
<level1 fetch_attribute="local-tag">/dialog-info/dialog[@local-tag]</level1>
</NotifyParsingRules>
<!-- Call pickup: fetch variable remote_uri from uri of NOTIFY body -->
<NotifyParsingRules type="variable" id="remote_uri" state="ringing">
<level1 fetch_attribute="uri">/dialog-info/dialog/remote/target[@uri]</level1>
</NotifyParsingRules>
<action>
<!-- Quick dial: depending in which states we want to allow this action -->
<invite target="$(ui_argument)" when="on press" states="calling, talking, offhook, idle"/>
<!-- Pick up -->
<invite target="$(remote_name)<$(remote_uri)>" when="on press" state="ringing" request_uri="$(remote_uri)" replaces="$(call_id);to-tag=$(remote_tag);from-tag=$(local_tag)"/>
<assign when="on notify" state="ringing">
<source value="kIconTypeFkeyBlfRinging"/>
<destination id="icon"/>
</assign>
<assign when="on notify" state="idle">
<source value="kIconTypeFkeyBlfIdle"/>
<destination id="icon"/>
</assign>
<assign when="on notify" state="ringing">
<source value="kIconTypeFkeyBlfRinging"/>
<destination id="icon"/>
</assign>
<assign when="on notify" state="calling">
<source value="kIconTypeFkeyBlfCalling"/>
<destination id="icon"/>
</assign>
<assign when="on notify" state="talking">
<source value="kIconTypeFkeyBlfTalking"/>
<destination id="icon"/>
</assign>
</action>
</key>
</ReplacementPlan> |
|
| 🔴 |  | 101 > | | offhook |
|
|
|---|
| goes onhook | dialog state => terminated NOTIFY
...
<?xml version="1.0"?>
<dialog-info
xmlns="urn:ietf:params:xml:ns:dialog-info"
version="..."
state="full"
entity="sip:101@...">
<dialog id="..."
direction='initiator'
call-id='...'
local-tag=""
remote-tag="">
<state>terminated</state>
<local>
<identity display="B">sip:101@...</identity>
<target uri="sip:101@...;line=...">
<param pname="x-line-id" pval="0" />
</target>
</local>
</dialog>
</dialog-info> |
| translate state => idle - quick dial allowed
- pick-up not allowed
...
<NotifyParsingRules type="state">
...
<level5 translates_to="idle"/>
</NotifyParsingRules>
...
<action>
<invite target="$(subscr_uri)"
when="on press"
states="idle"/>
<invite target="$(remote_uri)"
when="on press"
state="ringing"
request_uri="$(remote_uri)"
replaces="$(call_id);to-tag=$(remote_tag);from-tag=$(local_tag)"/>
</action> |
|
| ⚪️ |  | 101 | | idle |
|
|
|---|
| incoming call ringing | dialog state => early/proceeding NOTIFY
...
<?xml version="1.0"?>
<dialog-info
xmlns="urn:ietf:params:xml:ns:dialog-info"
version="..."
state="full" entity="...">
<dialog
id="..."
direction='recipient'
call-id='...'
local-tag="..."
remote-tag="...">
<state>early</state>
<local>
<identity display="B">
sip:101@...
</identity>
<target uri="sip:101@...;line=...">
<param pname="x-line-id" pval="0" />
</target>
</local>
<remote>
<identity display="C">
sip:102@...
</identity>
<target uri="sip:102@..."/>
</remote>
</dialog>
</dialog-info> |
| translate state => ringing - quick dial not allowed
- pick-up allowed
...
<NotifyParsingRules type="state">
<level1
translates_to="ringing">/dialog-info/dialog/state[.="early"]
</level1>
...
<level2
translates_to="ringing">/dialog-info/dialog/state[.="proceeding"]
</level2>
...
</NotifyParsingRules>
<NotifyParsingRules
type="variable"
id="call_id"
state="ringing">
<level1 fetch_attribute="call-id">/dialog-info/dialog[@call-id]</level1>
</NotifyParsingRules>
<NotifyParsingRules
type="variable"
id="remote_tag"
state="ringing">
<level1 fetch_attribute="remote-tag">/dialog-info/dialog[@remote-tag]</level1>
</NotifyParsingRules>
<NotifyParsingRules
type="variable"
id="local_tag"
state="ringing">
<level1 fetch_attribute="local-tag">/dialog-info/dialog[@local-tag]</level1>
</NotifyParsingRules>
<NotifyParsingRules
type="variable"
id="remote_uri"
state="ringing">
<level1 fetch_attribute="uri">/dialog-info/dialog/remote/target[@uri]</level1>
</NotifyParsingRules>
<action>
<invite target="$(subscr_uri)"
when="on press"
states="idle"/>
<invite target="$(remote_uri)"
when="on press"
state="ringing"
request_uri="$(remote_uri)"
replaces="$(call_id);to-tag=$(remote_tag);from-tag=$(local_tag)"/>
</action> |
|
| 🟠 |  | 102 > 101 | | ringing |
|
|
|---|
| incoming call accepted | dialog state => confirmed NOTIFY
...
<?xml version="1.0"?>
<dialog-info
xmlns="urn:ietf:params:xml:ns:dialog-info"
version="..."
state="full"
entity="sip:101@...">
<dialog
id="..."
direction='recipient'
call-id='...'
local-tag="..."
remote-tag="...">
<state>confirmed</state>
<local>
<identity display="B">sip:101@...</identity>
<target uri="sip:101@...;line=...">
<param pname="x-line-id" pval="0" />
<param pname="+sip.rendering" pval='yes' />
</target>
</local>
<remote>
<identity display="C">sip:102@...</identity>
<target uri="sip:102@..."/>
</remote>
</dialog>
</dialog-info> |
| translate state => talking - quick dial not allowed
- pick-up not allowed
...
<NotifyParsingRules type="state">
...
<level4
translates_to="talking">/dialog-info/dialog/state[.="confirmed"]
</level4>
</NotifyParsingRules>
...
<action>
<invite target="$(subscr_uri)"
when="on press"
states="idle"/>
<invite target="$(remote_uri)"
when="on press"
state="ringing"
request_uri="$(remote_uri)"
replaces="$(call_id);to-tag=$(remote_tag);from-tag=$(local_tag)"/>
</action> |
|
| 🔴 |  | 102 <> 101 | | talking |
|
|
|---|
| Incoming call terminated | dialog state => terminated NOTIFY
...
<?xml version="1.0"?>
<dialog-info
xmlns="urn:ietf:params:xml:ns:dialog-info"
version="8"
state="full"
entity="sip:101@...">
<dialog id="..."
direction='recipient'
call-id='...'
local-tag="..."
remote-tag="...">
<state>terminated</state>
<local>
<identity display="B">sip:101@...</identity>
<target uri="sip:101@...;line=...">
<param pname="x-line-id" pval="0" />
</target>
</local>
<remote>
<identity display="C">sip:102@...</identity>
<target uri="sip:102@..."/>
</remote>
</dialog>
</dialog-info> |
| translate state => idle - quick dial allowed
- pick-up not allowed
...
<NotifyParsingRules type="state">
...
<level5 translates_to="idle"/>
</NotifyParsingRules>
...
<action>
<invite target="$(subscr_uri)"
when="on press"
states="idle"/>
<invite target="$(remote_uri)"
when="on press"
state="ringing"
request_uri="$(remote_uri)"
replaces="$(call_id);to-tag=$(remote_tag);from-tag=$(local_tag)"/>
</action> |
|
| ⚪️ | | 101 | | idle |
|
|
|---|
| Outgoing call ringing | dialog state => early/proceeding NOTIFY
...
<?xml version="1.0"?>
<dialog-info
xmlns="urn:ietf:params:xml:ns:dialog-info"
version="13"
state="full"
entity="sip:101@...">
<dialog
id="..."
direction='initiator'
call-id='...'
local-tag="..."
remote-tag="">
<state>early</state>
<local>
<identity display="B">sip:101@...</identity>
<target uri="sip:101@...;line=...">
<param pname="x-line-id" pval="0" />
</target>
</local>
<remote>
<identity display="D">sip:103@...;user=phone</identity>
<target uri="sip:103@...;user=phone"/>
</remote>
</dialog>
</dialog-info> |
| translate state => calling - quick dial not allowed
- pick-up not allowed
...
<NotifyParsingRules type="state">
<level1
translates_to="ringing">/dialog-info/dialog/state[.="early"]
</level1>
<level1-1
translates_to="calling">/dialog-info/dialog[@direction="initiator"]
</level1-1>
<level2
translates_to="ringing">/dialog-info/dialog/state[.="proceeding"]
</level2>
<level2-1
translates_to="calling">/dialog-info/dialog[@direction="initiator"]
</level2-1>
</NotifyParsingRules>
...
<action>
<invite target="$(subscr_uri)"
when="on press"
states="idle"/>
<invite target="$(remote_uri)"
when="on press"
state="ringing"
request_uri="$(remote_uri)"
replaces="$(call_id);to-tag=$(remote_tag);from-tag=$(local_tag)"/>
</action> |
|
| 🔴 |  | 101 > 103 | | calling |
|
|
|---|
| Outgoing call accepted | dialog state => confirmed NOTIFY
...
<?xml version="1.0"?>
<dialog-info
xmlns="urn:ietf:params:xml:ns:dialog-info"
version="..."
state="full"
entity="sip:101@...">
<dialog
id="..."
direction='initiator'
call-id='...'
local-tag="..."
remote-tag="...">
<state>confirmed</state>
<local>
<identity display="B">sip:101@...</identity>
<target uri="sip:101@...;line=...">
<param pname="x-line-id" pval="0" />
<param pname="+sip.rendering" pval='yes' />
</target>
</local>
<remote>
<identity display="D">sip:103@...</identity>
<target uri="sip:103@..."/>
</remote>
</dialog>
</dialog-info> |
| translate state => talking - quick dial not allowed
- pick-up not allowed
...
<NotifyParsingRules type="state">
...
<level4
translates_to="talking">/dialog-info/dialog/state[.="confirmed"]
</level4>
</NotifyParsingRules>
...
<action>
<invite target="$(subscr_uri)"
when="on press"
states="idle"/>
<invite target="$(remote_uri)"
when="on press"
state="ringing"
request_uri="$(remote_uri)"
replaces="$(call_id);to-tag=$(remote_tag);from-tag=$(local_tag)"/>
</action> |
|
| 🔴 | | 101 <> 103 | | talking |
|
|
|---|
| Outgoing call terminated | dialog state => terminated NOTIFY
...
<?xml version="1.0"?>
<dialog-info
xmlns="urn:ietf:params:xml:ns:dialog-info"
version="..."
state="full"
entity="sip:101@...">
<dialog
id="..."
direction='initiator'
call-id='...'
local-tag="..."
remote-tag="...">
<state>terminated</state>
<local>
<identity display="B">sip:101@...</identity>
<target uri="sip:101@...;line=...">
<param pname="x-line-id" pval="0" />
</target>
</local>
<remote>
<identity display="D">sip:103@...</identity>
<target uri="sip:103@..."/>
</remote>
</dialog>
</dialog-info> |
| translate state => idle - quick dial allowed
- pick-up not allowed
...
<NotifyParsingRules type="state">
...
<level5 translates_to="idle"/>
</NotifyParsingRules>
...
<action>
<invite target="$(subscr_uri)"
when="on press"
states="idle"/>
<invite target="$(remote_uri)"
when="on press"
state="ringing"
request_uri="$(remote_uri)"
replaces="$(call_id);to-tag=$(remote_tag);from-tag=$(local_tag)"/>
</action> |
|
| ⚪️ | | 101 | | idle |
|
|
|---|
|
|
|
|
|
|
|---|
Questions
Below is a list of questions to be addressed as a result of this requirements document:
| Question | Outcome |
|---|
| Shall we visualize all possible translation states? | Alexander Feldt I'd agree, for these reasons: - Snom phones (acting as UAS) already provide all information in NOTIFY body
- It's cleaner, e.g. when the UAS goes offhook or calls somebody, currently "talking" is visualized, which is not true.
- It could be an advanced sales feature?
|
Shall we allow quick dial only in idle state? | Alexander Feldt Technically, we could allow quick dial in any state, except ringing... |
Shall we create new icons or reuse those already existing ones? | Alexander Feldt I really question icons, that are so small, that there is no visible difference to the user, like  and  , therefore - if we use them at all - I vote for better distinguishable icons. |
| How can a specific LED behaviour be addressed using XML definitions? | Alexander Feldt Currently not within XML definitions, it has to be configured via settings. |
| How can a specific label be addressed using XML definitions? | Alexander Feldt see label, but I haven't figured out how to define it correctly |
| How can a specific icon be addressed using XML definitions? | Alexander Feldt see icon, but I haven't figured out how to define it correctly |
| How shall the D8XX:PFK-mapping:BLF-XML:Monitoring:Visualization:Label:name-area be configured to use either number or display name? | Alexander Feldt The topic is even more complex: I assume the PFK label is generally too short to show longer extension number or names, i.e. some kind of scrolling must be used. But is this really helpful for the customer at all? |
| From the UX point of view: which visual aid is more important for the customer: LED or PFK label? | Alexander Feldt - The colour of the LED and if it is blinking => very important
- The label icon => basically not important, the LED is already showing everything, also the PFK label is not even shown by default
- The label name => important when it comes to call pickup, less important for other scenarios, so is it worth adding scrolling or should we keep it simpler?
- The label state => It is definitely an additional information, which cannot be shown with LED only, e.g. the difference between offhook, calling and talking
|
Tita Petre Is the above list of requirements enough input to create a proper testplan? |
|
Not Doing
- List the features discussed which are out of scope or might be revisited in a later release.
