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Good OEQs:

1.What is TTL value for VC Label?

2.what is difference between L3 and L2 FEC?

3. wat are pseudowire types for FR, ATM, Eth Port, Eth Vlan, HDLC, and PPP?

4.wat is size for Group ID field?

5.what is label adv mode for Targetted LDP?

Q1 What is TTL value for VC Label

ANS : For HDLC and PPP , The ingress LSR, R1, SHOULD set the TTL field of the VC label to a  value of 2.

 


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knowledge itself is a power 

Cool. Not sure about Cell Mode, but Frame Mode That is 2

is atm part correct for vc label ttl value

   "MPLS Pseudowire Type".  This type has 15-bit values.
   PW Type values 1 through 30 are specified as below
   and PW Type values 31 through 1024 are to be assigned by IANA,
   PW Type values 1025 through 4096 and 32767 are allocated by IETF                                        
   PW Type values 4097 through 32766 are reserved for vendor-    proprietary extensions and are to be assigned by IANA

   Pseudowire Type value allocations are specified below:
   PW type Description                                      
  =========================================================
   0x0001  Frame Relay DLCI ( Martini Mode )                
   0x0002  ATM AAL5 SDU VCC transport                       
   0x0003  ATM transparent cell transport                   
   0x0004  Ethernet Tagged Mode                             
   0x0005  Ethernet                                         
   0x0006  HDLC                                             
   0x0007  PPP                                              
   0x0008  SONET/SDH Circuit Emulation Service Over MPLS    
   0x0009  ATM n-to-one VCC cell transport                  
   0x000A  ATM n-to-one VPC cell transport                  
   0x000B  IP Layer2 Transport                              
   0x000C  ATM one-to-one VCC Cell Mode                     
   0x000D  ATM one-to-one VPC Cell Mode                     
   0x000E  ATM AAL5 PDU VCC transport                       
   0x000F  Frame-Relay Port mode                            
   0x0010  SONET/SDH Circuit Emulation over Packet          
   0x0011  Structure-agnostic E1 over Packet                
   0x0012  Structure-agnostic T1 (DS1) over Packet          
   0x0013  Structure-agnostic E3 over Packet                
   0x0014  Structure-agnostic T3 (DS3) over Packet          
   0x0015  CESoPSN basic mode                               
   0x0016  TDMoIP AAL1 Mode                                 
   0x0017  CESoPSN TDM with CAS                             
   0x0018  TDMoIP AAL2 Mode                                 
   0x0019  Frame Relay DLCI                                 
 

Cool. Long history in place of 5-6 words, but good elaboration, thank you, wat about other questions.

downstream on- demand label advertisement mode.  for targeted LDP sessions 

4.wat is size for Group ID field? 

with respect to what part of topic is the question releated 

i need clear idea 

and please correct me if any of the above answer are not correct 

if this is with respect to the PW ID FEC TLV, then Group id is a 1 byte field that contains the the group of PWs.  All ACs on the same interface get the same Group ID.

GroupID can be used to withdraw all VC labels that are associated with that group in 1 Label Withdraw message. This is also referred to as "Wild Card Label Withdraw".

Hi, For question number 5 as per MPLS fundamentals Page 388, the correct anwser should be downstream unsolicited

The main purpose of this LDP session between the PE routers is to advertise the VC label that is associated with the pseudowire. This label is advertised in a Label Mapping message using the downstream unsolicited label advertisement mode.