#
# SSFNET 1.1 Schema Dictionary 
#

schemas [   

# ----------------------------------------------------------------------
# Net: top-level schema for network configuration.  A Network is a 
# collection of hosts, routers, LANs, and subnetworks, plus connecting 
# links that define connections between or among their interfaces.   
#
# Net.cidr: names the cidr partition relative to that of the enclosing Net,
# if known; if uniformly omitted, Net will supply a default CIDR partition 
# isomorphic to the Net hierarchy, numbering links before subnets. 
#
# Net.ip: names the IP prefix for the Net, if known; if uniformly 
# omitted, Net will supply a default IP prefix according to the CIDR 
# partition in force (see Net.cidr above) a.b.c.d/m notation

 Net [
   frequency %I            # global time unit, in ticks per second (long int)

  _find .schemas.link
  
   host [ _extends .schemas.host 
     id %I idrange [from %I1! to %I1!]
     alignment %S
   ]

   router [ _extends .schemas.router
     id %I idrange [from %I1! to %I1!]
     alignment %S
   ]

   Net [ _extends .schemas.Net 
     id %I idrange [from %I1! to %I1!]
     alignment %S
     cidr %S
     ip %S 
   ]
   
   randomstream [
     generator %S
     stream %S
     reproducibility_level %S
   ]
   
 ]

# ----------------------------------------------------------------------
# host: a machine running a protocol graph, with zero or more configured 
# network interfaces.  "router" is synonymous with "host".  If a host 
# specification names an interface range and an IP address attribute,
# each interface in the range consumes successive IP addresses, using 
# the given attribute as the base address.

 host [
   graph %T1!:.schemas.graph   # protocol graph specification

   interface [ _extends .schemas.interface
     id %I idrange [from %I1! to %I1!]
     ip %S 
   ]

   _find .schemas.route        # Static routes for this host
   _find .schemas.nhi_route 
 ]

 router [_extends .schemas.host]


# ----------------------------------------------------------------------
# link: a group of connected interfaces.  We don't specify what routing
# or broadcast capabilities are present, or what symmetries of interface 
# properties must exist (e.g., matching bitrates) -- that's left to the 
# interfaces involved, which presumably must agree on the important points.
# "link.delay" is the only property common to the channel -- it represents
# the contribution of the link to total transmission latency (for example,
# lightspeed delays, latencies added by link-level equipment such as 
# repeaters).  It does not include interface-specific sources of delay 
# such as NIC latencies, buffering, or framing overhead. 
#
# link.cidr, link.ip: see Net.cidr, Net.ip above.  Same rules apply.

 link [                            
   attach %S2      # Link must have at least two endpoints
   cidr %S         # CIDR block level, 1 or more ints: L1/L2/L3/../Ln
   ip %S           # IP prefix, a.b.c.d/m notation
   delay %F        # link transmission delay, in seconds
 ]

# ----------------------------------------------------------------------
# interface: an abstraction of a single network interface such as an 
# ethernet card or a CSU/DSU.  Attributes bitrate, latency, buffersize 
# together describe the timing behavior of a stream of packets 
# entering or leaving the interface.  An interface that is not named in 
# any "link" attribute is considered "down" -- that is, unconnected. 

 interface [
   bitrate %F        # bits per second
   latency %F        # interface (NIC) latency, in seconds (on-card delay)
   buffer  %I        # transmission buffer size, in bytes 
   flaky %F          # drop packets with the given probability P, 0.<=P<=1.
   queue %S          # named packet queue discipline
   tcpdump %S        # 'tcpdump' traffic into the named file
 ]

# ----------------------------------------------------------------------
# graph: abstraction of a protocol graph, consisting of a list of  
# protocols to be configured and the names of classes to use. 
#
 graph [
   description %S      # optional protocol graph description string
   ProtocolSession [
     name %S1!         # symbolic tag, like "tcp" or "ip"
     use %S1!          # name of a class extending SSF.OS.ProtocolSession
   ]
 ]

# ----------------------------------------------------------------------
# ftable: Forwarding table for a given host. 

 ftable [                # Forwarding table 
   id %S                 # NHI address for which this is a forwarding table
   _find .schemas.route  
 ]     

# ----------------------------------------------------------------------
# route: single route to remote network or host.  Either 'interface' or  
# 'next_hop' must be provided, but not both.  If 'interface' is provided,
# the specified interface must be a point-to-point link, not a LAN, so that
# the peer interface who serves as next hop can be unique. 

 nhi_route [
   dest %S1!           # NHI address of destination or 'default'
   interface %I1       # interface ID to use
   next_hop %S1        # NHI address of next hop interface
  ]

 route [
   dest %S1!           # IP address of destination host or network
   interface %I1       # interface ID to use
   next_hop %S1        # IP address of next hop 
  ]
]