Knowledge (XXG)

Penultimate hop popping

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231: 22: 164:(LER). The benefit is that the LSR has to do a label lookup anyway and it doesn't make a difference whether this results in a label swap or pop. However, for the LER this saves one cycle of label lookup. 197:
PHP functionality is achieved by the LER advertising a label with a value of 3 to its neighbours. This label is defined as "implicit-null" and informs the neighbouring LSR(s) to perform PHP.
216: 194:
In large, loaded networks the additional time required for second label lookup can make a difference in the overall forwarding performance and reduce buffering.
272: 43: 179:) environment as it reduces the load on the LER. If this process didn't happen, the LER would have to perform at least 2 label lookups: 94: 113: 66: 265: 296: 73: 211: 187: 47: 149: 80: 258: 32: 62: 153: 51: 36: 291: 206: 87: 183:
The outer label, identifying that the packet was destined to have its label stripped on this router.
157: 156:. It refers to the process whereby the outermost label of an MPLS tagged packet is removed by a 145: 161: 242: 238: 172: 134: 230: 141: 285: 176: 138: 21: 168: 15: 190:(VRF) instance to use for the subsequent IP routing lookup. 246: 160:(LSR) before the packet is passed to an adjacent 266: 8: 50:. Unsourced material may be challenged and 273: 259: 114:Learn how and when to remove this message 144:and is a function performed by certain 207:What Is PHP (Penultimate Hop Popping) 7: 227: 225: 48:adding citations to reliable sources 186:The inner label, to identify which 245:. You can help Knowledge (XXG) by 14: 229: 20: 212:MPLS - Penultimate Hop Popping 188:Virtual Routing and Forwarding 167:The process is important in a 1: 313: 224: 63:"Penultimate hop popping" 127:Penultimate hop popping 297:Computer network stubs 44:improve this article 239:computer networking 158:label switch router 133:) is specified in 254: 253: 162:label edge router 124: 123: 116: 98: 304: 275: 268: 261: 233: 226: 169:Layer 3 MPLS VPN 119: 112: 108: 105: 99: 97: 56: 24: 16: 312: 311: 307: 306: 305: 303: 302: 301: 292:MPLS networking 282: 281: 280: 279: 222: 203: 120: 109: 103: 100: 57: 55: 41: 25: 12: 11: 5: 310: 308: 300: 299: 294: 284: 283: 278: 277: 270: 263: 255: 252: 251: 234: 220: 219: 214: 209: 202: 201:External links 199: 192: 191: 184: 122: 121: 28: 26: 19: 13: 10: 9: 6: 4: 3: 2: 309: 298: 295: 293: 290: 289: 287: 276: 271: 269: 264: 262: 257: 256: 250: 248: 244: 241:article is a 240: 235: 232: 228: 223: 218: 215: 213: 210: 208: 205: 204: 200: 198: 195: 189: 185: 182: 181: 180: 178: 174: 170: 165: 163: 159: 155: 151: 147: 143: 140: 136: 132: 128: 118: 115: 107: 104:December 2009 96: 93: 89: 86: 82: 79: 75: 72: 68: 65: –  64: 60: 59:Find sources: 53: 49: 45: 39: 38: 34: 29:This article 27: 23: 18: 17: 247:expanding it 236: 221: 217:MPLS PHP Lab 196: 193: 166: 142:Section 3.16 130: 126: 125: 110: 101: 91: 84: 77: 70: 58: 42:Please help 30: 286:Categories 74:newspapers 31:does not 152:enabled 154:network 146:routers 88:scholar 52:removed 37:sources 175:  148:in an 137:  90:  83:  76:  69:  61:  237:This 95:JSTOR 81:books 243:stub 177:2547 150:MPLS 139:3031 67:news 35:any 33:cite 173:RFC 135:RFC 131:PHP 46:by 288:: 274:e 267:t 260:v 249:. 171:( 129:( 117:) 111:( 106:) 102:( 92:· 85:· 78:· 71:· 54:. 40:.

Index


cite
sources
improve this article
adding citations to reliable sources
removed
"Penultimate hop popping"
news
newspapers
books
scholar
JSTOR
Learn how and when to remove this message
RFC
3031
Section 3.16
routers
MPLS
network
label switch router
label edge router
Layer 3 MPLS VPN
RFC
2547
Virtual Routing and Forwarding
What Is PHP (Penultimate Hop Popping)
MPLS - Penultimate Hop Popping
MPLS PHP Lab
Stub icon
computer networking

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