OEQ : what is a benefit of hello state timer

Q1. what is a benefit of hello state timer  

Q2. whats the benefit of ldp than tdp 

Q3. How many bits of VC label defiend in VC Header in AToM packet

Comments

  • Q1. what is a benefit of hello state timer

    The MPLS Traffic Engineering—RSVP Hello State Timer feature detects when a neighbor is down and quickly triggers a state timeout, which frees resources such as bandwidth that can be reused by other label switched paths (LSPs).

    RSVP hellos can be used to detect when a neighboring node is down. The hello state timer then triggers a state timeout. As a result, network convergence time is reduced, and nodes can forward traffic on alternate paths or assist in stateful switchover (SSO) operation. 

     


    Q2. whats the benefit of ldp than tdp 

    ldp open standard supports authentication.

    Q3. How many bits of VC label defiend in VC Header in AToM packet

    need to study


  • Side note for the LDP and TDP question:  It appears that the Cell Mode ATM only supports TDP?  Or maybe that's not stated right, it appears that the LS1010 only supports TDP, probably because of supported code revisions.

    Can anyone expand on this.

  • Side note for the LDP and TDP question:  It appears that the Cell Mode ATM only supports TDP?  Or maybe that's not stated right, it appears that the LS1010 only supports TDP, probably because of supported code revisions.

    Can anyone expand on this.


    LS1010 supports only TDP I am sure but for Back to Back Cell Mode I am not sure (10% ), this is to further expand what i said earlier:

    LDP and TDP

    The LDP and Cisco's proprietary TDP can both be used to advertise labels bindings for IGP prefixes. Although TDP and LDP are similar, there are a number of differences. Table 6-1 outlines some of the primary differences between LDP and TDP.


    LDP

    TDP

    IETF standard protocol

    Cisco proprietary protocol

    Uses an all-routers multicast address (224.0.0.2) for directly connected neighbor discovery

    Uses local broadcasts

    Uses UDP and TCP port 646 for neighbor discovery and session establishment

    Uses UDP and TCP port 711

    Provides optional MD5 authentication

    No optional MD5 authentication provided

     

  • Q1. what is a benefit of hello state timer  

    Q2. whats the benefit of ldp than tdp 

    Q3. How many bits of VC label defiend in VC Header in AToM packet

    ANS : 128 Bits

     

  • Side note for the LDP and TDP question:  It appears that the Cell Mode ATM only supports TDP?  Or maybe that's not stated right, it appears that the LS1010 only supports TDP, probably because of supported code revisions.

    Can anyone expand on this.


     

    LS1010 supports only TDP I am sure but for Back to Back Cell Mode I am not sure (10% ), this is to further expand what i said earlier:

    LDP and TDP

    The LDP and Cisco's proprietary TDP can both be used to advertise labels bindings for IGP prefixes. Although TDP and LDP are similar, there are a number of differences. Table 6-1 outlines some of the primary differences between LDP and TDP.

     

    LDP

    TDP

    IETF standard protocol

    Cisco proprietary protocol

    Uses an all-routers multicast address (224.0.0.2) for directly connected neighbor discovery

    Uses local broadcasts

    Uses UDP and TCP port 646 for neighbor discovery and session establishment

    Uses UDP and TCP port 711

    Provides optional MD5 authentication

    No optional MD5 authentication provided

     

     

     

    The primary benefit of LDP over prestandard TDP protocol is that it increase the number of platform on which MPLS interoperability can be achieved 

    ________________________________________________________________________________________________________________________________________________

     

  • Q3. How many bits of VC label defiend in VC Header in AToM packet

    ANS : 128 Bits

    huh??? how? isnt label is 32 bits only.

  • yes.. as I recall

    ATOM packet contains

    4 bytes tunnel label

    4 bytes VC label

    4 bytes control word

     

  • yes.. as I recall

    ATOM packet contains

    4 bytes tunnel label

    4 bytes VC label

    4 bytes control word


    I agree to this. Thanks good elaboration

     

  • oh while answering  i thought VC label as the Pseudowire ID FEC (which is 128)

     

    see interperting the question is also  more important in OEQ 

     

    thanks 

    :)[:)]

  • Psedowire ID FEC value is 128. It is not 128 bits. Labels are always 32 bits unless they are part of VPI/VCI.

     

     

  • Psedowire ID FEC value is 128. It is not 128 bits. Labels are always 32 bits unless they are part of VPI/VCI.

     

     

     

    Ha ha h aha, Thanks, i consfused with question and understood VC as VCI, ATOM and ATM though slight confusing, really need to be always careful.


  • Not related to the question, but the LS1010 does indeed support LDP.  

    LS1010 uptime is 5 hours, 4 minutes
    System returned to ROM by power-on
    System image file is "slot0:ls1010-wp-mz.121-27b.E3.bin"

    cisco LS1010 (R4600) processor with 65536K bytes of memory.
    R4600 CPU at 100Mhz, Implementation 32, Rev 2.0
    Last reset from power-on
    1 Ethernet/IEEE 802.3 interface(s)
    5 ATM network interface(s)
    125K bytes of non-volatile configuration memory.

    LS1010#sh mpls atm-ldp bindings 
     Destination: 150.1.102.0/24
        Tailend Switch ATM0/0/0 1/34 Active -> Terminating Active, VCD=53
        Tailend Switch ATM0/0/2 1/35 Active -> Terminating Active, VCD=59
     Destination: 150.100.100.254/32
        Tailend Switch ATM0/0/0 1/33 Active -> Terminating Active, VCD=52
        Tailend Switch ATM0/0/2 1/36 Active -> Terminating Active, VCD=60
     Destination: 150.1.109.0/24
        Tailend Switch ATM0/0/0 1/35 Active -> ATM0/0/2 Terminating Active, VCD=54
     Destination: 131.1.1.1/32
        Transit ATM0/0/2 1/33 Active -> ATM0/0/0 1/34 Active
     Destination: 150.1.101.0/24
        Tailend Switch ATM0/0/2 1/34 Active -> ATM0/0/0 Terminating Active, VCD=58
     Destination: 131.1.9.9/32
        Transit ATM0/0/0 1/42 Active -> ATM0/0/2 1/33 Active


    LS1010#sh mpls int 
    Interface              IP            Tunnel   Operational
    ATM0/0/0               Yes (tdp)     No       Yes         (ATM labels)
    ATM0/0/1               Yes (tdp)     No       No          (ATM labels)
    ATM0/0/2               Yes (ldp)     No       Yes         (ATM labels)
    LS1010#




    The point here is to not get "too comfortable" with what is configured as backbone behavior. 

    M



    On Feb 9, 2010, at 10:31 PM, scrlk wrote:

    image Avinashrai:


    image weaverap:

    Side note for the LDP and TDP question:  It appears that the Cell Mode ATM only supports TDP?  Or maybe that's not stated right, it appears that the LS1010 only supports TDP, probably because of supported code revisions.

    Can anyone expand on this.



     

    LS1010 supports only TDP I am sure but for Back to Back Cell Mode I am not sure (10% ), this is to further expand what i said earlier:

    LDP and TDP

    The LDP and Cisco's proprietary TDP can both be used to advertise labels bindings for IGP prefixes. Although TDP and LDP are similar, there are a number of differences. Table 6-1 outlines some of the primary differences between LDP and TDP.

     

    LDP

    TDP

    IETF standard protocol

    Cisco proprietary protocol

    Uses an all-routers multicast address (224.0.0.2) for directly connected neighbor discovery

    Uses local broadcasts

    Uses UDP and TCP port 646 for neighbor discovery and session establishment

    Uses UDP and TCP port 711

    Provides optional MD5 authentication

    No optional MD5 authentication provided

     
     


     

    The primary benefit of LDP over prestandard TDP protocol is that it increase the number of platform on which MPLS interoperability can be achieved 

    ________________________________________________________________________________________________________________________________________________

     



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  • Hahaha. This made me laugh, cos that's exactly what i was thinking "need to study". The only one that i could answer with 100% confidence was number 2.

  • Q3. How many bits of VC label defiend in VC Header in AToM packet

    ANS : 128 Bits

    huh??? how? isnt label is 32 bits only.

    The whole VC shim header is 32 bits, but the the question is asking the VC label, so I think the answer should be 20 bits.

    Bo

  • Hahaha. This made me laugh, cos that's exactly what i was thinking "need to study". The only one that i could answer with 100% confidence was number 2.


     

     

    ha haha h Yes, u rite.

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