Implicit null and explicit null

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..?
Thansk

1. If a router recieves a label value of 0, this implies the explicit null label. The router will swap the top label for label 0 and forward the packet. The next LSR will pop the packet.
2. If a label of 3 is recieved, this implies the implicit null label. The router in this case will pop the top label and forward the remaining. If there was only one label in the stack, it will forward the IP packet, else the labelled packet with the topmost label removed.
Check this link, and RFC 3032 for more explanation
http://www.cisco.com/en/US/tech/tk436/tk428/technologies_q_and_a_item09186a00800949e5.shtml#q13

Similar Messages

Difference between implicit enhancement and explicit enhancement

What is the difference between implicit enhancement and explicit enhancement .

Hi Peters,
Implicit enhancement option
Throughout the ABAP system, enhancement options are automatically available at certain pre-defined places. Some of the implicit options are:
u2022 At the end of all the programs (Includes, Reports, Function pool, Module pool, etc.), after the last statement
u2022 At the beginning and end of all FORM subroutines
u2022 At the end of all Function Modules
u2022 At the end of all visibility areas (public, protected and private) of local class
To view all the implicit options available in a source code, choose u2018Edit -> Enhancement Operations -> Show Implicit Enhancement Optionsu2019 from the editor.
Befor that you click on the spiral icon button in the application toolbar
Explicit enhancement option
The Implicit enhancement options are provided at specific source code places explicitly by SAP (Note that these enhancement definitions can also be created by partners and customers in their code).
There are two types of Explicit Enhancement options available. One which can be provided at a specific place - called Enhancement Point, and another which can be used to replace a set of statements u2013 called Enhancement Section. For this, we now have two new ABAP statements, viz.
u2022 ENHANCEMENT-POINT
u2022 ENHANCEMENT-SECTION
When the Enhancement-Section is implemented, only the implementation gets executed and the original code doesnu2019t get executed. This is a new technique, which didnu2019t exist previously in any of the old ways of enhancing, to exclude any standard SAP code from execution. Because of this, there can be only one active implementation of an Enhancement-Section. On the other hand, there can be multiple active implementations of an Enhancement-Point, in which case all the implementations will be executed with no guarantee in the order of execution.
For more information check the following link
[http://help.sap.com/saphelp_nw70/helpdata/en/94/9cdc40132a8531e10000000a1550b0/frameset.htm]
Thanks,
Surya

Difference between implicit cursor and explicit cursor.

hi all,
i have used explicit cursor, i know the way of using implicit cursor, but i don't what the difference between both.
Is they both are different. if yes y? which cursor is most reliable to use.
please tell me..
Thanks..

OK,
1- An IMPLICIT cursor is automatically declared by Oracle every time an SQL statement is executed The user will not be aware of this happening and will not be able to control or process
the information in an implicit cursor.
Example:
SET SERVEROUTPUT ON
BEGIN
UPDATE Customers
SET Cust_name = 'B'
WHERE Cust_name LIKE 'B%';
DBMS_OUTPUT.PUT_LINE(SQL%ROWCOUNT);
END;
2- An EXPLICIT cursor is defined by the program for any query that returns more than one row of data.
That means the programmer has declared the cursor within the PL/SQL code block. This declaration allows for the application to sequentially process each row of data as it is returned by the cursor.
Example :
DECLARE
CURSOR C_MyCursor IS
SELECT *
FROM bookings
WHERE Cust_no = 701;
see this post
http://comsci.liu.edu/~vasilaky/db2/cursors.htm :-)

Implicit enhancement and explicit enhancement

Hi Experts,
I have implemented one requirement using implicit enhancement but i want to check whethere there is any explicit nhancement or not. Please let me know if any one of you have idea on that in VF02 transaction to do changes in pricing details.
Regards,
Dileep.

Hi,
For VF02 Programe Name SAPMV60A goto this programe in this we have somany explisit Enhanacement spots, just click Binacular Icon(Find button) and paste Enhancement Spot it will disply list of explisit enhancement spots, select your spot and just right click and create spot and do changes according to your requirement.
Regards,
Sanjay Gogikar.

Difference between Implicit and Explicit Commit

Hi All ,
Can some one pls let me know the difference between Implicit commit and Explicit Commit .
Thanks in Advance..

>
Kalyan wrote:
> Hi,
>
> An explicit commit happens when we execute an SQL "commit" command.
>
> Implicit commits occur without running a commit command and occur only when certain SQL (DDL) statements are executed
>
> (Ie, INSERT,UPDATE OR DELETE Statements)
> >
> Hope this is clear & Helpful Short and Simple.
>
> Thanks
> Kalyan
Highlighted bit is incorrect.

Implicit and Explicit Enhancement

Hi Gurus ,
Can anyone please let me know about what is implicit enhancement and explicit enhancement.Steps involved in the same .
Thanks ...
ashok...

Hi
Implicit enhancement points are basically points within ABAP code where an enhancement point is implied, and in which case can be created. Examples of implicit enhancement points are at the beginning and end of FORMs, at the end of a program, include or function module etc. Below is a step by step demonstration of how to create and implicit enhancement point.
Explicit enhancement points are basically hooks already coded into the program by SAP at various points of the code. See program RIAUFMVK for examples of these! These are very easy to implement simply go into enhancement mode of SE80 and right click on the enhancement point where you want to add your code and choose Enhancement Implementation->Create Give it a name, description and assign it to a change request (should not be a Z package) and then simply add the code as normal
check the help
http://help.sap.com/saphelp_nw70/helpdata/en/94/9cdc40132a8531e10000000a1550b0/frameset.htm
Regards
anji

Implicit enhancement vs explicit enhancement

Hi,
Can any body tell me the difference between implicit enhancement and explicit enhancement?
My mail ID is [email protected]
Regards,
Jayapal

customer enhancements ECC
http://sap.ittoolbox.com/groups/strategy-planning/sap-projectmanagement/r3-47-vs-mysapsap-enterprise-883745#
http://www.absoft.co.uk/absoft/web/site/AbsoftSAPServices/Upgrade.asp
http://www.infosys.com/sap/Whitepaper_Upgrade_Dilemma_SAP_R3_Enterprise_or_mySAP_ERP.pdf
SAP Upgrade questions - Please give feedback
http://service.sap.com/erp
http://solutionbrowser.erp.sap.fmpmedia.com/ (Functional prespective)
http://service.sap.com/instguides --> mySAP Business Suite Applications --> mySAP ERP --> mySAP ERP 2005 --> Upgrade
http://help.sap.com/printdocu/core/Print46c/en/data/pdf/LOVC/LOVC.pdf
For Functionality Differences pls refer to the below site -
http://solutionbrowser.erp.sap.fmpmedia.com/
Exits are basically the hooks whcih SAP has provided to add your own code. There are two types of Exits:
1. Customer exits: Implemented as Function Modules within z includes. Anybody can change it and no access key is required.
2. User Exit: Implemented as subroutines within includes (any include except y or z includes). You need access for the specific include and then you can any subroutine (user exit) within that Include.
BADIs are the enhanced version of user exits where the same logic is implemented via classes and object (OOP)
Enchancement point is the latest once introduces with ECC6.0 . Not very sure about that but you can change it without any access key.
Please go through the following link which will help you understand the exits in a much better way:
http://help.sap.com/saphelp_nw04/helpdata/en/bf/ec07a25db911d295ae0000e82de14a/content.htm
http://www.sap-img.com/abap/what-is-the-difference-between-smod-and-cmod.htm
http://sap.niraj.tripod.com/id21.html
http://help.sap.com/saphelp_nw04/helpdata/en/c8/1975cc43b111d1896f0000e8322d00/frameset.htm
http://www.sap-img.com/ab038.htm
User Exits.
http://www.erpgenie.com/sap/abap/code/abap26.htm
http://www.sap-img.com/abap/a-short-tutorial-on-user-exits.htm
http://www.sapgenie.com/abap/code/abap26.htm
http://www.sap-img.com/abap/what-is-user-exits.htm
http://wiki.ittoolbox.com/index.php/HOWTO:Implement_a_screen_exit_to_a_standard_SAP_transaction
http://www.easymarketplace.de/userexit.php
http://www.sap-img.com/abap/a-short-tutorial-on-user-exits.htm
http://www.sappoint.com/abap/userexit.pdfUser-Exit
customer exits
https://www.sdn.sap.com/irj/sdn/go/portal/prtroot/docs/library/uuid/f1a7e790-0201-0010-0a8d-f08a4662562d
Menu Exit.
http://www.sappoint.com/abap/spmp.pdf
http://www.sappoint.com/abap/userexit.pdf
http://www.sapdevelopment.co.uk/enhance/mod_sapmenu.htm
http://www.sapdevelopment.co.uk/enhance/enhancehome.htm
Rewards if useful...................
Minal

Implicit-Null Label Value

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

Implicit null

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 advertise the implicit null label for directly connected routes and summarized routes."
but some of them told me that it will send implicit null for all routes it learns.
Which is true or is there any hidden meaning in connected and summarized routes???

Hi,
If the question is about IPv4 routes learned in a VRF, then implicit-null will not be used at all - neither for PE directly connected nor for summary routes. The reason is that a PE needs a VPN label to identify the VRF context, because the IP destination address alone can not do it as you might have overlapping IP addresses in different VRFs. If you have a look at the labels in a VRF (show mpls forwarding-table vrf ...) you will see "Aggregate" for VRF connected or VRF summary routes. This denotes, that the PE will use the VPN label to select the proper VRF context and then has to perform an additional IP lookup to figure out, who should get the packet. If a label is for a VRF connected network the IP packet could be for the PE or the CE sharing this network. A VPN label alone in this case will not be enough, a double lookup is needed.
So implicit-null is used for summary routes or directly connected routes in the global IP routing table of a PE.
Hope this helps!
Regards, Martin

What does "Implicit" and "Explicit" means????

-- after reading various Java books, articles, magazines, forums .... etc...
These two words: "Implicit" and "explicit" always appear on every text ...
-- Does implicit means "directly" and explicit means "indirectly"?
thanks

-- after reading various Java books, articles,
magazines, forums .... etc...
These two words: "Implicit" and "explicit" always
ways appear on every text ...
-- Does implicit means "directly" and explicit
licit means "indirectly"?
thanks"implicit" means that something is executed that is not written in your code
"explicit" means that whatever is executed specifically exists in the code.
For instance: "a base class constructor implicitly calls super() if you don't explicitly call super yourself."
That means even though it is not written in the code, the line:
super();
will be executed unless you explictily include a call to super() yourself, such as:
super(10, 14.6, "some text");

Difference between Implicit and Explicit Cursors

Hi All,
Can you just tell me what is the difference between implicit and explicit cursor?
Thanks,
Padma

Hi ,
Implicit Cursor means ,the cursors which are defined impplicitly.Here we use curosr variables as "SQL%found,sql%not found,sql%is open.."
but explicit cursors defined by us like if u create a cursor C1 then
c1%found,c1% not found ,c1%open
Thank you.

Implicit and explicit final

hey guys...
the specifictaion says when you define a class final, all methods are implicity final as well and they may be inlined. that's cool but why does the compiler explicit store the information into the class file that a method is final when the class is already defined as final..ok sounds complicated.. here an example :
public final class Test {
public void test() {}
}here the method is implicit final.. and in the class file it is stored as specified.
but why does the class contain the unnecessary information (?!) that the method is final when defined as such.. i mean it is already implicity final! example:
public final class Test {
public final void test() {}

hmm.. i was hoping someone else would throw out some input, but I can only guess that like I said before, it was an issue that was either not considered, or something that was considered to be an unnecessary step for the compiler.
I don't have a disassembler on hand to do any complex tests, but just out of curiosity, I ran a very simple one. I created a class with a whole lot of methods leaving the final as an implicit modifier and compiled. Then changed them all the be explicitly declared as final and compiled. The byte size of the output was identical, regardless of how many methods I added. I don't know that this is necessarily significant, but certainly raises some questions.

Implicit and explicit Type conversion using Type object in heap

Hi,
I am surprised how Implicit and explicit Type conversion works using Type object in heap. for example when implicit type conversion occur what pointer it returns to object and similarly with explicit type conversion.

Hello,
>> I am surprised how Implicit and explicit Type conversion works using Type object in heap.
For Implicit conversions: Typical examples are conversions from smaller to larger integral types, and conversions from derived classes to base classes. For the first one, the reference would be different which means it would return a different pointer to
a new object. For the reference type, it actually points to the same memory location, you could use the object.ReferenceEquals() to check it.
For Explicit conversions (casts):Typical examples include numeric conversion to a type that has less precision or a smaller range, and conversion of a base-class instance to a derived class. For first one, it would perform the same with implicit conversions.
While for the conversion of conversion of a base-class instance to a derived class, actually, there's no built-in way to do this conversion.
Regards.
We are trying to better understand customer views on social support experience, so your participation in this interview project would be greatly appreciated if you have time. Thanks for helping make community forums a great place.
Click
HERE to participate the survey.

Advertise implicit-null label for static routes

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 because somehow we need to do rate-limit on the PE interface connecting to the core network instead of the interface connecting to CE. As the incoming packets still got labelled, the rate-limit is skipped. So we want to stop the PE creates label for the static routes or advertises them with implicit null label. Thanks in advance.

Calvin,
Bear in mind that if you only enter the "no mpls ldp advertise-label" command, LDP will stop propagating all labels, which might not ba what you want. If you selectively want to propagate certain labels, then you need to also use "mpls advertise label for " as Shivlu suggested.
Regards,

What is Implicit Enhancement and what is explicit enhancement.

Hi,
I am new to Enhancements.
What is implicit enhancement and what is explicit enhancement.
where exactly we have to create those.
Thanks and regards,
swami
Moderator message - Please search before asking - post locked
Edited by: Rob Burbank on Oct 26, 2009 9:43 AM

Hi Swaminath ,
Go through the following Blogs on enhancement Frame work. It will help u in understanding This concept in detail.
/people/thomas.weiss/blog/2007/12/12/the-three-use-cases-of-the-enhancement-and-switch-framework--part-1
/people/thomas.weiss/blog/2008/01/07/the-three-use-cases-of-the-enhancement-and-switch-framework--part-2
/people/thomas.weiss/blog/2008/01/14/the-three-use-cases-of-the-enhancement-and-switch-framework--part-3
/people/thomas.weiss/blog/2008/01/23/the-three-use-cases-of-the-enhancement-and-switch-framework--part-4-the-many-ways-to-enhance-a-sap-application-with-the-new-framework
/people/thomas.weiss/blog/2008/02/04/the-three-use-cases-of-the-enhancement-and-switch-framework--part-5-the-basics-about-switching
/people/thomas.weiss/blog/2008/02/29/second-try-the-three-use-cases-of-the-enhancement-and-switch-framework--part-6-the-re-integration-of-the-sap-industry-solutions-into-the-erp-core
/people/thomas.weiss/blog/2008/03/11/the-three-use-cases-of-the-enhancement-and-switch-framework-part-7--the-enhancement-package-strategy-of-sap-erp-60
/people/thomas.weiss/blog/2009/01/15/how-to-get-the-most-from-the-enhancement-and-switch-framework-as-a-customer-or-partner--tips-from-the-experts
Regards,
Eswar

Implicit null and explicit null

Similar Messages

Maybe you are looking for