1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
|
The LAN test suite (test-suite-lan.tcl) performs the following tests:
- lan-routing-flat
- lan-routing-hier - these two tests are designed to validate LANs
under flat and hierarchical routing and specifically the
functionality of the lanRouter object. The topology is the same
in both cases:
0 2----------5
| |
---+----+-----+-- LAN virtual node (3)
|
4-------------1
with a TCP sender attached to node 4 and a TCP receiver at node
5. Here packets are not replicated at the LAN, because they are
unicast and replication is costly. Packets flow from node 4 to
1, then the lanRouter object determines the next hop of the
packet (node 2) and packets with unicast MAC address of node 2
are put on the shared medium (channel). Since the packet has a
unicast MAC address of 2, MAC classifier delivers it to 2 only,
at which point it is forwarded to 5. TCP acknowledgements are
delivered in a similar fashion in reverse direction.
WARNING: the current nam animation (as of 11/23/98) shows that
all packets (including unicast) are replicated and delivered to
every node on the LAN. This is misleading, because in the
unicast case packets are delivered only to the next hop node.
- lan-broadcast: tests the broadcast behavior of mac classifier.
4-------0 2
| | \
(vLAN node 3) --+-------+ 5
| /
1
A CBR agent at node 4 is sending unicast packets to a receiver
at node 5. But in this case the MAC classifier is explicitly
running in the broadcast mode and even though the IP
consequently the MAC address is unicast, packets are fanned out
and delivered both to 2 and to 1. Both 2 and 1 receive the
packet, classify it as addressed to 5 and forward accordingly.
Thus the receiver at 5 receives two copies of the same packet.
- lan-abstract: tests the behavior of the abstract lan implemented
using a DropTail queue as the contention mechanism
0 2
| |
---+----+-----+-- abstract LAN node (4)
| |
1 3
A TCP senders are attached to node 0 and node 2 with TCP receivers
present at node 1 and node 3 respectively. Packets are queued
and sent on the LAN on a FIFO basis. ACK and packets share
the same queue. Default queue size of 50 packets.
- lan-mactrace: validates the behavior of MAC level collision traces
on a LAN
0 2
| |
---+----+-----+-- vLAN node (4)
| |
1 3
A CBR agent is attached to node 0 and node 2 which sends packets at
a regular interval of 0.5 seconds to node 1 and mode 3 respectively.
Both the agents start at the same time and hence always experience a
collision. This is recored as a 'c' in the trace files.
After a collision, the source double the time it defers, before it
attempts to transfer a packet again ie: binary exponential backoff.
|
