Implicit-Null Label Value

10-11  Source: Network gathering  Views:0 

Advertisement
Hi,
A quick question. Does anyone know if when said that last hop router signals implicit null to penultimate router it actually sends the advertisement (LDP for example) with a label value of 3 or is there another way to signal that?
If so, I assume that with MPLS-TE LSPs it's the same thing but with RSVP Resv message...
Thanks,
David
Hello David,
in fact Label value 3 has the meaning "implicit null". So whatever protocoll is used (LDP or RSVP) this is the signaled value to activate PHP (penultimate hop popping).
From RFC 3032 section 2.1
" iv. A value of 3 represents the "Implicit NULL Label". This is a label that an LSR may assign and distribute, but which never actually appears in the encapsulation. When an LSR would otherwise replace the label at the top of the stack with a new label, but the new label is "Implicit NULL", the LSR will pop the stack instead of doing the replacement. Although this value may never appear in the encapsulation, it needs to be specified in the Label Distribution Protocol, so a value is reserved."
Hope this helps! Please rate all helpful posts!
Martin
Related articles
  • Implicit-Null Label Value 10-11

    Hi, A quick question. Does anyone know if when said that last hop router signals implicit null to penultimate router it actually sends the advertisement (LDP for example) with a label value of 3 or is there another way to signal that? If so, I assume

  • Advertise implicit-null label for static routes 10-11

    Hi, I want to ask if there is any way to change the label or stop adveritise label for an static route. Normally LDP advertises an Implicit Null label for directly connected routes. We want to do similar thing for static routes. We need to do this is

  • Implicit & Explicit Null Labels 10-11

    Hi.. I am a bit confused in Implicit and Explicit null labels. The RFC Says as follows : IMPLICIT NULL LABEL:This label value is only legal at the bottom of the label stack. It indicates that the label stack must be popped, and the forwarding of the

  • Implicit null and explicit null 10-11

    Hi, 1) If a router receives a label of 0,what is it supposed to do..? label poppoing or swapping th label with 0. 2) If a router receives the label of 3,whether it pops the label or swap the incoming label with the value of 3..? Thansk1. If a router

  • Implicit null 10-11

    hai experts, just now stepped into mpls world. i am refering the book "MPLS Fundamentals" by Luc De Ghein. In the implicit null portion the author states that " PHP is the default mode in cisco IOS.In case of ipv4 over mpls ,cisco ios only

  • Passing null/empty values from a actionscript VO to a Coldfusion ORM object 10-11

    This is the situation. If you have an actionscript VO that binds to a Coldfusion ORM object via the RemoteClass metadata and some of the values are not set, null, or empty strings and you pass it from Flex to Coldfusion then the Coldfusion deserializ

  • Passing null/empty values from Flex to a Coldfusion ORM object 10-11

    This is the situation. If you have an actionscript VO that binds to a Coldfusion ORM object via the RemoteClass metadata and some of the values are not set, null, or empty strings and you pass it from Flex to Coldfusion then the Coldfusion deserializ

  • Remove null & empty values 10-11

    I created a report with multiple fields. I would like to create a generic formula in which it evaluates all the values and if it found a null or empty value it will be replaced by a 'N/A'. I was searching in the forums and I found the following formu

  • How to trap null return values from getters when using Method.invoke()? 10-11

    Hi, I am using Method.invoke() to access getters in an Object. I need to know which getters return a value and which return null. However, irrespective of the actual return value, I am always getting non-null return value when using Method.invoke().

  • Null display value in List of Values 10-11

    Hello In Page item ---> List of Value ---> Null display value I need to give a different value depending on language I tried using an item in the "Null Display Value" e.g. &P1_Display_value. This does not work ... I get " &P1_

  • How to Avoid overlapping data label values in Pie Chart 11-30

    Hi, I am facing the problem when the data is more my pie chart data label value is overlapping. I tried with showing outside the data label value but customer is not accepting ,and i used the CollectedPie  option also but still its overlapping .So pl

  • Conditionally display items based on null LOV value 11-30

    Hello, I've seen several examples that do what I'd like to do but with different implementations. Perhaps someone can steer me in the right direction... I have a pop-up lov that pulls a list of names from various places. If, however, the name cannot

  • Apex 4 Cascading LOV's how to set a child LOV back to null return value 11-30

    Hi, My problem is I am using the new Dynamic Actions to implement Cascading LOV functionality in Apex 4 which means not having to submit the page to update child LOVs after parent LOV changes. What I am finding is that when you change the parent LOV

  • Report Builder 2.0 loses parameter Null default value when deployed 10-11

    When a parameter is set to a default value of (Null) and the report is saved to the sever, the default is lost when the report is re-opened in RB2.  This problem doesn't seem to occur in BIDS.  I've tried to use an expression to set the value to Syst

  • Alter Table Add column not null default value 10-11

    I want to add two columns to a table with not null and default as 0 for both columns Can i write the whole in one statement or do i have to split statement I tried this, but didn't work alter table DWSODS01.DWT00301_ORD_DTL_OMS add ( COMB_ORD_FLG NUM

  • T-sql 2012 accept null parameter values 10-11

    The following t-sql 2012 works fine in sql management studio. However when I place it in a .net 2010 web form application, I am told the sql does not work when the parameter values are null. Thus can you tell me what I can change in the sql below tha

  • Using '=' to check for NULL column value 10-11

    We are currently encountering an issue where 10.1.0.5 is happily accepting a check on a column for a null value with what I have always known to be an invalid syntax. For instance: select col1 from my table where col1=null Although this is wrong and

  • Verify if a report has a null column value with JavaScript ? 10-11

    Hi, I have report. User can add new rows through a form. Before the user leaves the application I would like to use JavaScript to check if a certain column has some null values. I built my JavaScript for the before logout and it's working properly, b

  • Bug: when fetching arrays of rows with null data values 10-11

    Using Oracle ODBC Driver 8.01.73.00 or 8.01.74.00 (called 8.1.7.3.0 and 8.1.7.4.0 on the Oracle downloads page). When fetching multiple rows, and where some of the data is null, the the indicator variable quite often (but not always) has incorrect va

  • How to skip null ColumnSeries values in a clustered ColumnChart? 10-11

    (this is a simple but difficult problem; call-out to clever chart-coders): When displaying multiple ColumnSeries in a clustered ColumnChart (3.5 SDK), the default behavior is to allocate a blank space when one of the series has no value in the datapr