OUTPUT-101 : Frame-Relay Traffic Shaping

Often knowing the necessary show commands is not enough, you need to understand the output.
Here is a good example and breakdown of each of the fields with the command:

show traffic-shape

 VC                      = 'DLCI's'
 Access List             = 'Used to shape traffic of common type for separation'
 Target Rate             = 'CIR in bits'
 Byte-Limit              = 'Bc+Be ie the size the token bucket, express in BYTES'
 Sustain bits/int        = 'Bc value per Tc, (int is short for interval or Tc)'
 Excess bits/int         = 'Be value'
 Interval (ms)           = 'Tc value'
 Increment (bytes)       = 'How many bytes of token replenished each Tc, ie Bc value in bytes'
 Adapt Active            = 'Shows Adaptive shaping has been enabled. If a BECN is received, the flow is throttled back'

What else can be set about the configuration here?
The interface have 3 DLCI’s defined.
DLCI’s 413 and 405 have a CIR of 56k. This was not configured. This is default behaviour. When ‘frame-relay traffic-shaping’ is enabled each DLCI on that interface will be allocated a 56k CIR unless changed. Here it is clear that DLCI 403 has a map-class policy applied.

Oh and Merry Christmas guys :D

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R&S Quick Notes – Frame-Relay/PPP

Frame-Relay

  • DHCP on a frame interface : “frame-relay interface-dlci 555 protocol ip 166.166.166.2”
  • When asked to disable INARP, be sure to do so on physical interfaces any multipoint sub-interfaces.
  • If you see 0.0.0.0 frame mappings, save your config and reload.
  • The backup command CANNOT be used on FR physical interfaces. (no way to detect when back up)
  • Back-to-Back frame connections, disable keepalives with “no keep”
  • LMI keepalives sent every 10 seconds. This interval can NOT be changed.
  • LMI Full Status Updates are requested every 60 seconds. CAN be changed with “frame lmi-n391dte”.
  • To ping local interface IP, add a mapping for local IP with any valid DLCI.

PPP

  • To do “?” in authentication password, use either ESC-Q or CRTL-V.
  • If two routers both using CHAP has the same hostname “no ppp chap ignoreus” is required.
  • “ppp authentication eap” can be used as alternative to chap when md5 needed.
  • “ppp link minimum” – amount of links required for a MLP bundle to up.
  • With CHAP and PAP, know which side is the client and who is authenticating who!
  • Know PPPoFR, MLP, and the mix combination formats

Frame-Relay interface states

Frame-Relay tends to create confusion in many areas from the network types, to routing protocols.

One typical confusion I’d like to point out is the behavior in states of physical interfaces compared to sub-interfaces when running frame-relay.

First let me explain two definitions: LMI and DLCI

Local Management Interface (LMI) is a set of enhancements to the basic Frame-Relay specification. LMI virtual circuit status messages provide communication and synchronization between a Frame Relay DTE (your router) and a DCE device (typically the provider’s frame-relay switches). These messages are used to periodically report on the status of Permanent Virtual Circuits (PVCs), which prevents data from being sent into black holes (that is, over PVCs that no longer exist). In short, LMI takes care of the communication between the DCE and DTE.

Datalink connection identifiers (DLCIs) uniquely identifies the Virtual circuits that provide a bidirectional communication path from one DTE device to another.

Continue reading “Frame-Relay interface states”