Page of 428
Download Table of ContentsContents Print This PagePrint Bookmark
   
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 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428

Advertisement

If a network does not run IGP TE extension, the network administrator is unable to identify from which
part of the network the required bandwidth can be obtained when setting up a CR-LSP. In this case, loose
explicit route (ER-hop) with required resources is used. The established CR-LSP, however, may change
when the route changes, for example, when a better next hop becomes available. If this is undesirable,
the network administrator can set up the CR-LSP using route underpinning to make it a permanent path.
Administrative group and affinity attribute
The affinity attribute of an MPLS TE tunnel identifies the properties of the links that the tunnel can use.
Together with the link administrative group, it decides which links the MPLS TE tunnel can use.
Reoptimization
Traffic engineering is a process of allocating or reallocating network resources. You can configure it to
meet desired QoS.
Normally, service providers use some mechanism to optimize CR-LSPs for best use of network resources.
They can do this manually but CR-LSP measurement and tuning are required. Alternatively, they can use
MPLS TE where CR-LSPs are dynamically optimized.
Dynamic CR-LSP optimization involves periodic calculation of paths that traffic trunks traverse. If a better
route is found for an existing CR-LSP, a new CR-LSP is established to replace the old one, and services are
switched to the new CR-LSP.

RSVP-TE

Two QoS models are available: IntServ and DiffServ.
Resource Reservation Protocol (RSVP) is designed for IntServ. It reserves resources on each node along a
path. RSVP operates at the transport layer but does not participate in data transmission. It is an Internet
control protocol similar to ICMP.
RSVP features:
Unidirectional.
Receiver oriented. The receiver initiates resource reservation requests and is responsible for
maintaining the reservation information.
Using soft state mechanism to maintain resource reservation information.
Extended RSVP can support MPLS label distribution and allow resource reservation information to be
transmitted with label bindings. This extended RSVP is called "RSVP-TE," which is operating as a
signaling protocol for LSP tunnel setup in MPLS TE.
Basic concepts
Soft state
Soft state is a mechanism used in RSVP-TE to periodically refresh the resource reservation state on
a node. The resource reservation state includes the path state and the reservation state. The path
state is generated and refreshed by the Path message. The reservation state is generated and
refreshed by the Resv message. A state is to be removed if no refresh messages are received for it
in certain interval.
Resource reservation style
Each LSP set up using RSVP-TE is assigned a resource reservation style. During an RSVP session, the
receiver decides which reservation style to use for this session and which LSPs to use.
The following reservation styles are available:
93

Advertisement

   Related Manuals for HP 10500 SERIES

Comments to this Manuals

Symbols: 0
Latest comments: